Release of the 1Q18 results

Public Disclosure - Belo Horizonte, April 20, 2018. Usinas Siderúrgicas de Minas Gerais S.A. - Usiminas (B3: USIM3, USIM5 and USIM6; OTC: USDMY and USNZY; LATIBEX: XUSIO and XUSI) today releases its first quarter (1Q18) results. Operational and financial information of the Company, except where otherwise stated, are presented based on consolidated figures, in Brazilian Real, according to International Financial Reporting Standards (IFRS). All comparisons made in this release take into consideration the fourth quarter of 2017 (4Q17), unless stated otherwise. Release of the 1Q18 results The main operational and financial indicators were: Steel sales volume of 1.1 million tons; Iron ore sales volume of 1.8 million tons; Consolidated Adjusted EBITDA of R$641.2 million and Adjusted EBITDA margin of 19.8%; Working capital on 03/31/18 of R$3.0 billion; Cash position on 03/31/18 of R$1.6 billion; Investments on 03/31/18 of R$64.9 million. Highlights R$ million - Consolidated 1Q18 4Q17 1Q17 Chg. 1Q18/4Q17 Steel Sales Volume (000 t) 1,089 1,090 930 0% Iron Ore Sales Volume (000 t) 1,806 1,500 643 20% Net Revenue 3,244 3,077 2,351 5% COGS (2,632) (2,662) (1,870) -1% Gross Profit (Loss) 612 414 481 48% Net Income (Loss) 157 (45) 108 - EBITDA (Instruction CVM 527) 622 373 528 67% EBITDA Margin (Instruction CVM 527) 19% 12% 23% + 7 p.p. Adjusted EBITDA 641 450 533 42% Adjusted EBITDA Margin 20% 15% 23% + 5 p.p. Investments (CAPEX) 65 107 23-39% Cash and Cash Equivalents 1,563 2,314 2,416-32% Market Data 03/31/18 Index Consolidated Results B3: USIM5 R$10.92/share Performance of the Business Units: USIM3 R$12.31/share - Mining - Steel EUA/OTC: USNZY US$3.25/ADR - Steel Processing - Capital Goods LATIBEX: XUSI 2.54/share Subsequent events XUSIO 2.92/share Capital Markets Balance Sheet, Income and Cash Flow Statements 1Q18 Results 1

Economic Outlook In the 1Q18, the main economic indicators showed consistent recovery of the Brazilian economy. According to the Instituto Brasileiro de Geografia e Estatística (IBGE), industrial production recorded a 4.3% increase in the first two months of 2018 over the same period in 2017. Steel intensive consumption sectors have had even more expressive increases. Capital goods production advanced 12.6% and durable goods, 17.9%. The improvement is reflected in the industrial business confidence index, which, according to the National Industrial Federation (CNI), reached 59 points in March, above the historical average index of 54 points. The low inflation rate is on its way to fulfilling the forecast, and the exchange rate floated in an interval between R$3.14 and R$3.34/US$1.00 in the 1Q18, in spite of recent volatility in the international markets, with the exchange rate reaching R$3.42/US$1.00 on 04/10/2018. Below, are listed market projections according to the Focus Report of 04/06/2018: Summary of Economic Indicators Focus Projection Indicators 2016 2017 2018 GDP (IBGE) -3.5% 1.0% 2.8% Industrial GDP -4.0% 0.1% 3.7% Industrial Production (IBGE) -6.4% -2.4% 4.3% Inflation - IPCA 6.3% 2.9% 3.5% Interest - Selic (end of period) 13.8% 7.0% 6.25% Exchange rate R$/US$ (end of period) 3.26 3.31 3.30 Source: IBGE, Focus Report (04/06/2018) 1Q18 Results 2

Economic and Financial Performance Comments on the Consolidated Results Net Revenue Net revenue in the 1Q18 was R$3.2 billion, against R$3.1 billion in the 4Q17, due to better performance of all of the Company s Business Units, with a highlight for higher sales volume and prices of steel in the domestic market, higher sales prices of steel on the export market and higher volume of iron ore exports. Net Revenue Breakdown 1Q18 4Q17 1Q17 Domestic Market 82% 81% 90% Exports 18% 19% 10% Total 100% 100% 100% Cost of Goods Sold - COGS COGS in the 1Q18 totaled R$2.6 billion, stable compared to that in the 4Q17, which was R$2.7 billion. For further information, see the Business Unit section of this release. Gross profit grew from R$414.5 million in the 4Q17 to R$612.1 million in the 1Q18, presenting a 47.7% improvement. Gross margin was 18.9%, against 13.5% in the 4Q17, as shown below: Gross Margin 1Q18 4Q17 1Q17 18.9% 13.5% 20.4% Operating Expense and Income In the 1Q18, sales expenses were R$76.1 million, against R$70.2 million in the 4Q17, an 8.5% increase, mainly due to expenses with the higher volume of iron ore exported in the period, partially compensated by lower expenses with personnel and general expenses. General and administrative expenses in the 1Q18 totaled R$102.8 million, 5.3% lower than those in the 4Q17, which were R$108.5 million, mainly due to lower expenses with personnel and third party services. In the 1Q18, other operating expense and income were a negative R$109.6 million, against a negative R$165.1 million in the 4Q17, mainly due to: Asset impairment in the amount of R$74.9 million in the 4Q17, relative to the Goodwill resulting from the acquisition of the subsidiaries Rios Unidos and Modal, and the associate company Codeme. There was no event of this nature in the 1Q18; Lower provisions for legal liabilities by R$13.8 million in the 1Q18, which totaled R$15.0 million, against R$28.8 million in the 4Q17. These effects were partially compensated by: Negative result in the sale of surplus electrical energy of R$13.6 million in the 1Q18, against a positive R$7.1 million in the 4Q17; Lower tax credits by R$28.2 million, which were R$19.3 million in the 1Q18, against R$47.5 million in the 4Q17; Thus, net operating expenses and income were R$288.5 million negative in the 1Q18, against R$343.8 million negative in the 4Q17. 1Q18 Results 3

In this manner, the Company s operational margin showed the following performance: EBIT Margin 1Q18 4Q17 1Q17 10.0% 2.3% 7.8% Adjusted EBITDA Adjusted EBITDA is calculated from net income (loss), reversing income tax and social contribution, financial result, depreciation, amortization and depletion, and equity in the results of Associate and Joint Subsidiary, not including impairment of assets. The adjusted EBITDA includes the proportional participation of 70% of Unigal and other joint subsidiary companies. EBITDA Breakdown Consolidated (R$ thousand) 1Q18 4Q17 1Q17 Net Income (Loss) 157,185 (44,851) 108,318 Income Tax / Social Contribution 73,803 (4,620) 58,855 Financial Result 133,774 172,084 54,581 Depreciation, Amortization 257,104 250,337 306,341 EBITDA - Instruction CVM - 527 621,866 372,950 528,095 Equity in the Results of Associate and Subsidiary Companies (41,154) (51,982) (37,080) Joint Subsidiary Companies proportional EBITDA 60,490 56,646 41,754 Impairment of Assets - 72,764 - Adjusted EBITDA 641,202 450,378 532,769 Adjusted EBITDA in the 1Q18 was R$641.2 million, against R$450.4 million in the 4Q17, mainly due to better performance of all of the Company s Business Units, with a highlight for the Steel Unit, which reached an Adjusted EBITDA of R$568.6 million in the quarter. For further information, see the Business Unit section of this release. Adjusted EBITDA margin in the 1Q18 was 19.8%, against 14.6% in the 4Q17 as shown below: Adjusted EBITDA Margin 1Q18 4Q17 1Q17 19.8% 14.6% 22.7% 1Q18 Results 4

Financial Result In the 1Q18, net financial result was a negative R$133.8 million, against a negative R$172.1 million in the 4Q17, a 22.3% decrease, mainly due to lower losses related to exchange variation, caused by the devaluation of the Real against the Dollar of 4.4% in the 4Q17 against a devaluation of 0.5% in the 1Q18. Below, please find a summary of the Financial Result: Financial Result - Consolidated R$ thousand 1Q18 4Q17 1Q17 Change 1Q18/4Q17 Net Currency Exchange Variation (25,481) (56,091) 55,617-55% Swap Transactions Market Cap. 1,466 (1,905) 1,299 - Interest on Financial Asset and Monetary Effects 37,390 67,605 102,626-45% Other Financial Income 39,504 37,692 56,525 5% Interest and Monetary Effects over Financing and Taxes Payable in Installments (132,552) (157,407) (218,796) -16% Other Financial Expenses (54,101) (61,978) (51,852) -13% FINANCIAL RESULT (133,774) (172,084) (54,581) -22% + Appreciation / - Depreciation of Exchange Rate (R$/US$) -0.5% -4.4% 2.8% + 3.9 p.p. Equity in the Results In the 1Q18, the results of equity of Associate and Subsidiary Companies were jointly R$41.2 million, against R$52.0 million in the 4Q17, mainly due to lower contribution of Unigal and Codeme, partially compensated by better results of MRS Logística. Net Profit (Loss) In the 1Q18, the Company accounted a net profit of R$157.2 million, reversing a net loss of R$44.9 million in the 4Q17. This represented a recovery of R$202.1 million in this period. Working Capital In the 1Q18, working capital was R$3.0 billion, against R$2.8 billion in the 4Q17, an increase of R$157.0 million, generated by the increase in Inventories and in Accounts Receivable, partially compensated by the increase in Suppliers and in Other Liabilities. The following is noteworthy: Increase in inventories of R$208.0 million, mainly due to the increase in production costs related to price increases of raw materials, mainly coal and purchased slab; Increase in the balance of Accounts Receivable by R$187.0 million, due to higher sales volume in the period in the Steel Unit by R$70.0 million, in Capital Goods by R$63.0 million and in Steel Processing Unit by R$52.0 million; Increase of R$130.0 million in Suppliers, mainly related to the purchase of slabs from third parties; 1Q18 Results 5

Increase in Other Liabilities of R$70.0 million, mainly related to the increase in the balance of forfaiting operations by R$52.0 million, in addition to increase in the balance of advances to customer by R$19.0 million; Increase in the balance of Salaries by R$27.0 million, mainly related to the Profit and Results Sharing Program. Investments (CAPEX) In the 1Q18, investments totaled R$64.9 million, 39.4% lower compared to those in the 4Q17, which were R$107.1 million. Of the total investments made in this period, approximately 87% was made to the Steel Unit, 6% to the Mining, 2% to Capital Goods and 5% to Steel Processing Units. Indebtedness On 03/31/18, gross consolidated debt was R$5.7 billion, a decrease of R$976.6 million over that on 12/31/17, mainly due to the following payments: On 01/18/18, full payment of the Notes issued by its subsidiary Usiminas Commercial Ltd. in 2008 (Eurobonds) in the amount of US$400.0 million, of which around US$180.0 were paid and around US$220.0 million returned to the Company s cash account by reason of the repurchase of the part of the Notes, made in 2013; Additionally, on 03/15/18 the Company paid the amount corresponding to the total of excess amount of cash (Cash Sweep), calculated based on the Company s financial statements of the period ended on 12/31/2017, in the total amount of R$378.8 million, as a partial amortization of the amounts of principal due by Usiminas to the Creditors. On 03/31/18, debt composition by maturity was 0.5% short term and 99.5% long term. In the same period, the parcel of foreign currency debt was 19%, against 26% on 12/31/17. Net consolidated debt on 03/31/18 was R$4.1 billion, against R$4.3 billion on 12/31/17. The net debt/ebitda ratio at the end of the 1Q18 was 1.8x, against 2.0x in the 4Q17. The following chart demonstrates the consolidated debt indexes on 03/31/18: R$ thousand 31-Mar-18 31-Dec-17 Change 31-Mar-17 % Short Term Long Term TOTAL TOTAL Mar18/Dez17 TOTAL Local Currency 29,800 4,560,460 4,590,260 81% 4,908,319-6% 5,161,235-11% TJLP 1,538 335,530 337,068-359,896-6% 378,799-11% CDI 14,313 4,200,600 4,214,913-4,498,775-6% 4,731,318-11% Others 13,949 24,330 38,279-49,648-23% 51,118-25% Foreign Currency* 1,134 1,088,307 1,089,441 19% 1,747,954-38% 1,718,079-37% Gross Debt 30,934 5,648,767 5,679,701 100% 6,656,273-15% 6,879,314-17% Cash and Cash Equivalents - - 1,562,549-2,314,288-32% 2,415,637-35% Net Debt - - 4,117,152-4,341,985-5% 4,463,677-8% (*)100% of total foreign currency is US dollars denominated Total Indebtedness by Index - Consolidated Change Mar18/Mar17 1Q18 Results 6

The graph below demonstrates the cash position and debt amortization profile in millions of Real on 03/31/18: 1,563 Duration: R$: 50 months US$: 56 months 303 1,086 1,083 1,083 1,083 754 208 208 208 208 1,260 408 144 77 877 875 875 874 610 92 133 11 331 26 11 15 77 107 Cash 2018 2019 2020 2021 2022 2023 2024 2025 2026 Local Currency Foreign Currency Performance of the Business Units Intercompany transactions are on arm s-length basis (market prices and conditions) and sales between Business Units are carried out as sales between independent parties. Usiminas - Business Units Mining Steel Steel Processing Capital Goods Mineração Usiminas Ipatinga Mill Soluções Usiminas Usiminas Mecânica Cubatão Mill Unigal Income Statement per Business Units - Non Audited - Quarterly R$ million Mining Steel* Steel Processing Capital Goods Adjustment Consolidated 1Q18 4Q17 1Q18 4Q17 1Q18 4Q17 1Q18 4Q17 1Q18 4Q17 1Q18 4Q17 Net Revenue 252 206 3,003 2,761 703 667 113 51 (827) (608) 3,244 3,077 Domestic Market 77 61 2,580 2,329 703 667 113 51 (827) (608) 2,646 2,500 Exports 175 145 423 432 - - - - - - 598 577 COGS (179) (154) (2,460) (2,371) (656) (629) (74) (54) 737 545 (2,632) (2,662) Gross Profit (Loss) 73 52 543 390 47 38 39 (4) (90) (62) 612 414 Operating Income (Expenses) (56) (48) (196) (267) (26) (28) (12) (3) 2 2 (288) (344) Selling (25) (18) (37) (36) (10) (11) (3) (4) (1) (1) (76) (70) General and Administrative (6) (3) (78) (86) (13) (14) (9) (8) 3 3 (103) (108) Others, Net (25) (27) (81) (145) (3) (2) - 8 - - (109) (166) EBIT 17 4 347 123 21 11 27 (7) (88) (60) 324 71 Adjusted EBITDA 49 42 568 404 29 19 32 (2) (37) (12) 641 450 Adj.EBITDA Margin 19% 20% 19% 15% 4% 3% 29% -4% 5% 2% 20% 15% *Consolidated 70% of Unigal 1Q18 Results 7

I) M I N I N G In the 1Q18, the average iron ore price in the international market increased 13.25%, against that in the 4Q17, accounting an average price in the quarter of US$74.26/t, i.e., around US$8.69/t higher than in the previous quarter. Pressures on Chinese steel production, mainly by the adoption of trade restrictions related to environmental control during the winter have caused the plants to give preference to higher quality ore purchases, which due to market scarcity, have pressured prices upward. Because domestic steel supply was also pressured due to these environmental measures, steel prices have also been maintained at a higher level, resulting in high profits for the plants, which, in turn, are able to pay more for better quality raw materials. The quarter was also marked by price oscillations up to US$16.90/t between minimums and maximums. Comparing the monthly averages in the quarter, prices varied widely in February and March, falling from US$77.46/t in February to US$69.70/t in March, and in this last month, reached the minimum of US$63.05/t. With respect to recent price declines, uncertainty and insecurity in regard to the protectionist measures announced by the US against China has significantly contributed to these market oscillations, because it has negatively impacted prices and the medium-term outlook for the Chinese steel industry, consequently affecting iron ore prices. Operational and Sales Performance Mining In the 1Q18, production volume was 1.36 million tons, against 1.54 million tons in the 4Q17. Sales volume accounted in the 1Q18 were 1.8 million tons, against 1.5 million tons in the 4Q17, highlighting a 51% increase in exports. Production and sales volumes are shown in the chart below: Iron Ore Thousand tons 1Q18 4Q17 1Q17 Change 1Q18/4Q17 Production 1,361 1,539 681-12% Sales - Third Parties - Domestic Market 167 179 28-7% Sales - Exports 1,084 716-51% Sales to Usiminas 555 605 615-8% Total Sales 1,806 1,500 643 20% Comments on the Business Unit Results - Mining Net revenue in the 1Q18 was R$251.9 million, against R$205.9 million in the 4Q17, a 22.4% growth, mainly in function of higher sales volume. Although average prices in the 1Q18 remained at US$74.4/t, price projections which indicate a decline of around US$10/t resulted in a reduction in gross revenue of approximately R$33.0 million as a Mark to Market (MtM) provision reducing revenue from sales with floating prices not delivered at the period. Cash cost per ton was R$58.1/t in the 1Q18, against R$50.2/t in the 4Q17, a 15.7% increase, due to lower dilution of fixed costs in function of lower production volume by 11.6%, despite an 8.9% decrease in total fixed costs. Cost of Goods Sold (COGS) was R$178.6 million in the 1Q18, against R$153.7 million in the 4Q17. COGS per ton was R$98.6/t, against R$102.2/t, a 3.5% decrease in the 4Q17, mainly due to lower maritime freight costs, due to higher exported volume in FOB terms in the 1Q18. Net operating expenses and income were R$56.4 million negative in the 1Q18 against R$49.0 million negative in the 4Q17, a 15.1% increase mainly related to higher selling expenses in function of the greater volume of exports in the period. 1Q18 Results 8

Thus, Adjusted EBITDA was R$49.0 million in the 1Q18, against R$41.4 million in the 4Q17, an 18.2% growth. Adjusted EBITDA margin was 19.5% in the 1Q18, against 20.1% in the 4Q17, a 0.6 percentage point decline. Investments (CAPEX) Investments in the 1Q18 were R$3.7 million, against R$9.1 million in the 4Q17, applied to sustaining CAPEX. Stake in MRS Logística Mineração Usiminas has a stake in MRS Logística through its subsidiary UPL- Usiminas Participações e Logística S.A. MRS Logística is a concession that controls, operates and monitors the Brazilian Southeastern Federal Railroad Network (Malha Sudeste da Rede Ferroviária Federal). The company operates in the railway transportation segment, connecting the states of Rio de Janeiro, Minas Gerais and São Paulo, and its core business is transporting, with integrated logistics, bulk cargo in general, such as iron ore, finished steel products, cement, bauxite, agricultural products, pet coke and containers. MRS transported 37.5 million tons in the 1Q18, a decrease of 11.4% in relation to those in the 4Q17, in accordance to the seasonality of the period. II) S T E E L Usiminas estimates that flat carbon steel consumption in the 1Q18 was 2.6 million tons, with 88% of the volume supplied by local plants and 12% imported. This means a 3% decline compared to the 4Q17, due to seasonal factors. Compared to the same period in the previous year, there was an 8% increase. Imports totaled 318 thousand tons, a slight increase of 2% compared to those in the 4Q17. The behavior of the main consumer segments for flat steel in the 1Q18 is shown below: Automotive: Vehicle production reached 700 thousand vehicles in the first quarter of the year, a 15% increase compared to the same period in the previous year. The increase was driven by recovery in domestic sales in line with an improvement in family income, higher consumer confidence and declining interest rates. For 2018, ANFAVEA (National Auto Manufacturers Association) has announced a forecast of a 12% sales increase, 13% in production and 5% in exports. Industrial: The improvement in machinery and equipment (M&E) production of 8% was accounted in the first two months of 2018 in relation to the same period in 2017. With regard to performance of the main sub-segments of M&E, the highlight is the growth in machinery production for extraction and construction which grew 47% and of industrial and commercial machinery of 5%. For 2018, Tendências Consulting foresees a 9% growth in the segments domestic production. Domestic and Commercial Appliances: The household segment continues to show positive numbers. According to the IBGE, industrial production in the Electrical Appliances segment recorded a 26% increase compared to the first two months of 2018 with those in 2017. The outlook is for improvement in credit conditions, with decrease in interest rates, allowing for positive results also in 2018. Civil Construction: The production of typical inputs for Civil Construction (ICC-IBGE) recorded a 3% increase in the first two months of 2018. The recovery of the building industry has been slower than in other sectors, however, for 2018, growth is forecast at 6%, according to Tendências Consulting. 1Q18 Results 9

Distribution: According to the National Steel Distributors Institute (INDA), flat steel sales in the associated distribution network grew 10% in the 1Q18 compared to the previous quarter and 17% compared to those in the 1Q17. Inventories were reduced over the first quarter, with the present level equivalent to 3.1 months of turnover, based on sales in March. Production - Ipatinga and Cubatão Plants In the 1Q18, crude steel production at the Ipatinga plant was 715 thousand tons, against 747 thousand tons in the 4Q17. In the 1Q18, finished product production in the Ipatinga and Cubatão plants totaled 1.07 million tons, stable in relation to the 4Q17, which as 1.10 million tons. Production of Crude and Rolled Steel Thousand tons 1Q18 4Q17 1Q17 Change 1Q18/4Q17 Total Crude Steel 715 747 737-4% Total Rolled Steel 1,074 1,096 965-2% Sales Total sales volume in the 1Q18 was 1.09 million tons of steel, in line with sales in the 4Q17, which also totaled 1.09 million tons. In the domestic market, sales were 919.5 thousand tons in the 1Q18, against 894.0 thousand tons in the 4Q17, a 2.9% increase. Export sales 169.6 thousand tons in the 1Q18, against 196.1 thousand tons in the 4Q17, a 13.5% decrease. The share in domestic sales volume was 84% of the total, and 16% went to the export market. The evolution of sales is shown in the following chart: The main export destinations are shown below: 1Q18 Results 10

Sales Volume Breakdown Thousand tons 1Q18 4Q17 1Q17 Change 1Q18/4Q17 Total Sales 1,089 100% 1,090 100% 930 100% 0% Heavy Plates 111 10% 112 13% 112 12% -1% Hot Rolled 338 31% 286 29% 266 29% 18% Cold Rolled 368 34% 404 31% 297 32% -9% Galvanized 260 24% 276 26% 232 25% -6% Slabs 12 1% 12 1% 23 2% -1% Domestic Market 920 84% 894 87% 825 89% 3% Heavy Plates 103 11% 95 13% 107 12% 8% Hot Rolled 304 33% 276 33% 256 28% 10% Cold Rolled 283 31% 268 29% 242 26% 6% Galvanized 224 24% 247 26% 200 21% -9% Slabs 6 1% 8 1% 20 2% -25% Exports 170 16% 196 13% 105 11% -13% Heavy Plates 8 5% 16 13% 5 1% -51% Hot Rolled 34 20% 10 5% 10 1% 232% Cold Rolled 85 50% 135 44% 54 6% -37% Galvanized 36 21% 29 27% 32 3% 23% Slabs 7 4% 6 2% 4 0% - Comments on the Business Unit Results - Steel Net revenue in the Steel Unit was R$3.0 billion in the 1Q18, 8.8% higher than in the 4Q17, which was R$2.8 billion, due to better prices by 7.9% in the domestic market and 13.8% in the export market, in addition to higher domestic sales volume by 2.9%. In the 1Q18, cash cost per ton was R$1,875/t, against R$1,770/t in the 4Q17, a 5.9% increase comparing periods, mainly due to higher cost with purchased slabs by 10.3% and with coal by 7.4%, partially compensated by lower costs of iron ore by 4.9%. In the 1Q18, 401 thousand tons of slabs were processed, against 415 thousand tons in the 4Q17. Cost of Goods Sold COGS was R$2.5 billion in the 1Q18, stable in comparison with the 4Q17. COGS per ton was R$2.260/t in the 1Q18, a 3.9% increase compared to that in the 4Q17, which was R$2,176/t, mainly due to consumption of inventories produced in prior periods at higher costs. Sales expenses were R$36.7 million in the 1Q18, 1.8% higher than those in the 4Q17, which were R$36.1 million, mainly due to reversion of provision for doubtful accounts in the 4Q17, against a provision of R$1.0 million in the 1Q18. In the 1Q18, general and administrative expenses totaled R$77.7 million, against R$86.4 million in the 4Q17, a 10.1% decrease, mainly due to lower expenses with personnel and third party services. Other operating expense and income totaled a negative R$81.1 million in the 1Q18, against a negative R$143.4 million in the 4Q17, a 43.5% decrease, mainly due to: Asset impairment accounted in the 4Q17 in the amount of R$73.0 million, relative to the Goodwill resulting from the acquisition of the subsidiariy Rios Unidos and the associate company Codeme. There was no such effect in the 1Q18; Lower provision for legal liabilities by R$16.9 million in the 1Q18, which totaled R$13.8 million, against R$30.7 million in the 4Q17; Additionally, there were lower non-absorbed equipment stoppage expenses in the amount of R$69.2 million in the 1Q18, of which R$65.5 million referred to depreciation, against R$69.6 million in the 4Q17, of which R$66.1 million referred to depreciation. 1Q18 Results 11

These effects were partially compensated by: Lower result with tax recovery, which totaled R$1.5 million in the 1Q18 against R$19.8 million in the 4Q17. Lower tax credits by R$28.2 million in the 1Q18, which totaled R$19.3 million, against R$47.5 million in the 4Q17; Negative result in the sales of surplus electrical energy by R$14.3 million in the 1Q18, against a positive result of R$7.0 million in the 4Q17; In this manner, net operating expense and income totaled R$195.5 million in the 1Q18, against R$265.9 million in the 4Q17. Thus, Adjusted EBITDA reached R$568.6 million in the 1Q18, against R$404.9 million in the 4Q17. Adjusted EBITDA margin was 18.9% in the 1Q18, against 14.7% in the 4Q17, a 420 basis points increase. Investments (CAPEX) In the 1Q18, investment totaled R$56.4 million, against R$89.9 million in the 4Q17, applied to sustaining CAPEX. III) S T E E L P R O C E S S I N G Soluções Usiminas SU Soluções Usiminas operates in the distribution, services and small-diameter tubes markets nationwide, offering its customers high-value added products. It serves several economic segments, such as automotive, auto parts, civil construction, distribution, electro-electronics, machinery and equipment and household appliances, among others. Sales to business units Distribution, Services/Just-In-Time and Tubes accounted for 34%, 57% and 9%, respectively. Comments on the Business Unit Results Steel Processing Net revenue in the 1Q18 was R$702.8 million, 5.4% greater than in the 4Q17, which was R$667.0 million, due to higher average prices in the period by 4.3%, as well as higher sales and services volume by 1.1%. In the 1Q18, cost of goods sold was R$656.0 million, against R$628.6 million in the 4Q17, a 4.4% increase, in function of the sale of products produced and/or purchased at higher costs. Net operating expense and income was a negative R$26.1 million, 5.3% lower compared with that in the 4Q17, which was a negative R$27.5 million, mainly due to lower expenses with personnel and third party services. Thus, Adjusted EBITDA in the 1Q18 was R$28.5 million, against R$18.6 million in the 4Q17, a 56.5% increase. Adjusted EBITDA margin was 4.1% in the 1Q18, against 2.8% in the 4Q17, an increment of 130 basis points. 1Q18 Results 12

IV) C A P I T A L G O O D S Usiminas Mecânica S.A. Usiminas Mecânica is a Brazilian capital goods company dedicated to the fabrication and assembly of metallic structures, shipbuilding and offshore platforms, oil and gas, industrial assembly and equipment fabrication, foundry and railcar manufacture. Main Contracts In the 1Q18, the main contracts were for the mining industry, oil and gas and industrial assembly. Comments on the Business Unit Results Capital Goods In the 1Q18, net revenue was R$113.3 million, 123.3% higher than in the 4Q17, which was R$50.7 million, in function of an amendment in contract on assembly in the mining industry signed and entirely recognized in the 1Q18. However, this effect is not recurrent. Due to the stagnation of projects in the oil and gas and infrastructure sectors in the country, there has not yet been a relevant and sustainable improvement in Usiminas Mecânica's operations. In the 1Q18, Usiminas Mecânica reached a gross profit of R$39.6 million, against a loss of R$3.7 million in the 4Q17, due to higher margins obtained with the amendment to a contract in the mining industry. Adjusted EBITDA in the 1Q18 was a positive R$32.7 million, against a negative EBITDA of R$2.2 million in the 4Q17. Adjusted EBITDA margin in the 1Q18 was 28.9%, against a negative 4.3% in the 4Q17, a 3,320 basis points improvement. Events Subsequent to the End of the Quarter General Ordinary and Extraordinary Shareholders Meetings: On 04/25/18, the Meeting at Usiminas will deliberate on the following matters: In the Extraordinary Meeting: Proposed amicable solution for the Civil Liability Lawsuit filed by the Company against its former Chief Executive Officer, whose filing was approved at the Annual Shareholders Meeting of 04.27.2017 ( Liability Lawsuit ), by means of the Company renouncing the claim presented in the Liability Lawsuit, in accordance with article 487, III, c, of the Brazilian Civil Procedure Code, without any payment, reimbursement or indemnification from party to party, each one of them bearing and paying (directly or indirectly) all the fees and expenses of their own attorneys (including the expenses and contractual and any attorneys fees ( honorários contratuais e sucumbenciais )) and their own court costs and expenses ( custas e despesas processuais ). In the Ordinary Meeting: (1) Receive the report from the administration, examine, discuss and vote on the financial statements and annual report of the administration for fiscal year ending on 12/31/17 (2); (2) destination of the net profit accounted in fiscal year 2017 and approval of the capital budget for fiscal year ; (3) proposal of the administration for payment of dividends and definition of the date for payment of same; (4) establish the global amount for remuneration of the administrators for the period until the General Ordinary Shareholders Meeting of 2019; (5) election of the Board of Directors Sitting Members and Substitutes for the term until the General Ordinary Shareholders Meeting of 2020, including deliberation of the number of sears to be filled in this election; (6) election of the Chairman of the Board; and (7) election of the sitting members and substitutes of the Fiscal Council for a term until the General Ordinary Meeting of the Company of 2019, as well as determination of the respective remuneration. The documents pertaining to the matters in the Order of the Day can be found at the disposition of the Shareholders at the Company s headquarters and on the sites of the CVM (www.cvm.gov.br), B3 (www.b3.com.br) and the Company s website (www.usiminas.com/ri). 1Q18 Results 13

Amendment to the existing Shareholders Agreement of Usiminas: In furtherance to their joint notice to, and the corresponding relevant fact issued by, Usinas Siderúrgicas de Minas Gerais S/A Usiminas ( Usiminas or the Company ) on 02/08/2018, Nippon Steel & Sumitomo Metal Corporation ( NSSMC ) and Ternium Investments S.à r.l. ( Ternium ), jointly informed, together with Previdência Usiminas ( PU ), that, on 04/10/2018, NSSMC and its affiliate Nippon Usiminas Co., Ltd. ( NU ), Ternium and its affiliates Confab Industrial S.A. ( Confab ), Prosid Investments S.A. ( Prosid ) and Ternium Argentina S.A. (formerly known as Siderar. S.A.I.C.) ( Ternium Argentina ), PU, Metal One Corporation ( Metal One ) and Mitsubishi Corporation do Brasil S.A. ( Mitsubishi ) (collectively, the Parties ), have entered into a binding new Usiminas shareholders agreement (the New SHA ) that, effective as from the date hereof, amends and restates the existing Usiminas Amended and Restated Shareholders Agreement dated 01/16/2012 (the SHA ) in its entirety. The New SHA has the same termination date as the SHA. Governance of Usiminas: The New SHA reflects the new governance provisions described in NSSMC and Ternium s 02/08/2018 joint notice, including, among others, the rules for the nomination of the Chairperson of the Board of Directors and the CEO and the rules relating to the composition and nomination of the Executive Board. In addition, the Parties have agreed to incorporate as Registered Shares under the New SHA all the ordinary shares subscribed for by each of Confab, NSSMC, Prosid, Ternium Argentina and Ternium in connection with the capital increase approved at the Company in March 2016. Exit provisions: The New SHA reflects also the exit procedures and mechanics disclosed on 02/08/2018 which shall apply with respect to all Registered Shares held by NSSMC, NU, Metal One, Mitsubishi, and to all Registered Shares held by Confab, Prosid, Ternium Argentina and Ternium, and any other person joining the New SHA as member of any such groups, as well as any new ordinary shares subscribed for by any such parties in connection with any future capital increases at Usiminas. In light of the incorporation of additional shares as Registered Shares as described above, the percentage of Registered Shares that a selling group of shareholders may retain under the exit mechanism was lowered from 10% to 6.67%. Standstill: The New SHA also incorporates the standstill provisions disclosed on 02/08/2018, which now encompass and are binding on all Parties. Other Covenants and Agreements: The parties to the New SHA intend to jointly review the existing Bylaws and other internal corporate rules and regulations of Usiminas and its subsidiaries to ensure that they do not and will not conflict with the governance rules of the New SHA. 1Q18 Results 14

Capital Markets Usiminas Performance Summary - B3 (USIM5) 1Q18 4Q17 Change 1Q18/4Q17 1Q17 Change 1Q18/1Q17 Number of Deals 928,584 872,253 6% 692,202 34% Daily Average 15,476 14,784 5% 11,165 39% Traded - thousand shares 941,460 1,174,102-20% 1,010,930-7% Daily Average 15,691 19,900-21% 16,305-4% Financial Volume - R$ million 10,579 10,627 0% 4,872 117% Daily Average 176 180-2% 79 124% Maximum 12.88 10.58 22% 5.62 129% Minimum 9.17 7.69 19% 3.91 135% Closing 10.92 9.10 20% 4.46 145% Market Capitalization - R$ million 13,684 11,403 20% 5,589 145% Performance in the B3 Usiminas common shares (USIM3) closed the 1Q18 quoted at R$12.31 and its preferred shares (USIM5) at R$10.92. In the 1Q18, USIM3 and USIM5 appreciated 13.7% and 20.0%, respectively. In the same period the Ibovespa presented an 11.7% appreciation. Foreign Stock Markets OTC New York Usiminas has American Depositary Receipts (ADRs) traded on the over-the-counter market: USDMY is backed by common shares and USNZY, by Class A preferred shares. On 03/31/18, USNZY ADRs, which have higher liquidity, were quoted at US$3.25, presenting an appreciation of 17.3%. LATIBEX Madrid Usiminas shares are traded on the LATIBEX the Madrid Stock Exchange: XUSI as preferred shares and XUSIO as common shares. On 03/31/18, XUSI closed quoted at 2.54, appreciating 11.9% in the quarter. XUSIO shares closed quoted at 2.92, registering appreciation of 11.9% in the period. 1Q18 Results 15

For further information: INVESTOR RELATIONS DEPARTMENT Leonardo Karam Rosa leonardo.rosa@usiminas.com 55 31 3499-8550 Danielle Ap. Maia danielle.aparecida@usiminas.com 55 31 3499-8148 Press: please contact through e-mail imprensa@usiminas.com Visit the Investor Relations site at: www.usiminas.com/ri Or móbile Access at: m.usiminas.com/ri 1Q18 Conference Call Results - Date 04/20/2018 In Portuguese - Simultaneous Translation into English Brasília time: at 11:00 a.m. New York time: at 10:00 a.m. Dial-in Numbers: Dial-in Numbers: Brazil: (+55 11) 3193-1001 / 2820-4001 USA: (1 646) 828-8246 Audio replay available at (55 11) 3193-1012 / 2820-4012 Pincode for replay: 330306# - Portuguese Pincode for replay: 460306# - English Audio of the conference call will be transmitted live via Internet See the slide presentation on our website: www.usiminas.com/ri Statements contained in this release, relative to the business outlook of the Company, forecasts of operating and financial income and references to growth prospects are mere forecasts and were based on the expectations of Management in relation to future performance. These expectations are highly dependent on market conduct, the economic situation in Brazil, its industry and international markets and, therefore, are subject to change. 1Q18 Results 16

Balance Sheet - Assets - Consolidated IFRS - R$ thousand Assets 31-Mar-18 31-Dec-17 31-Mar-17 Current Assets 6,749,345 7,254,755 6,893,598 Cash and Cash Equivalents 1,562,549 2,314,288 2,415,637 Trade Accounts Receivable 1,741,954 1,555,494 1,173,118 Taxes Recoverable 323,538 362,465 291,519 Inventories 2,971,493 2,763,496 2,814,559 Advances to suppliers 5,208 4,332 6,617 Financial Instruments 15 12 68,652 Other Securities Receivables 144,588 254,668 123,496 Non-Current Assets 18,627,433 18,729,722 19,410,970 Long-Term Receivable 4,192,447 4,115,862 4,068,519 Deferred Income Tax & Social Contribution 3,029,743 3,046,112 3,040,718 Deposits at Law 754,423 675,600 667,712 Accounts Receiv. Affiliated Companies 2,952 3,147 3,623 Taxes Recoverable 53,638 54,881 96,074 Financial Instruments 2,648 1,184 748 Others 349,043 334,938 259,644 Investments 1,092,905 1,054,052 1,150,372 Property, Plant and Equipment 12,669,891 12,882,618 13,488,122 Intangible 672,190 677,190 703,957 Total Assets 25,376,778 25,984,477 26,304,568 Balance Sheet - Liabilities and Shareholders' Equity - Consolidated IFRS - R$ thousand Liabilities and Shareholders' Equity 31-Mar-18 31-Dec-17 31-Mar-17 Current Liabilities 2,325,040 3,046,420 2,458,976 Loans and Financing and Taxes Payable in Installments 30,934 1,010,471 609,555 Suppliers, Subcontractors and Freight 1,107,295 976,917 683,157 Wages and Social Charges 212,949 188,735 180,941 Taxes and Taxes Payables 83,861 96,523 123,035 Accounts Payable Forfaiting 527,353 475,251 606,752 Financial Instruments - 0 71,225 Dividends Payable 119,942 75,644 22,003 Customers Advances 100,115 81,394 55,094 Others 142,591 141,485 107,214 Long-Term Liabilities 7,756,145 7,754,093 8,445,852 Loans and Financing and Taxes Payable in Installments 5,648,767 5,645,802 6,269,759 Actuarial Liability 1,032,979 1,050,324 1,139,376 Provision for Legal Liabilities 688,777 668,964 665,078 Financial Instruments - - - Environmental Protection Provision 162,126 158,333 146,721 Others 223,496 230,670 224,918 Shareholders' Equity 15,295,593 15,183,964 15,399,740 Capital 13,200,295 13,200,295 13,200,295 Reserves & Revenues from Fiscal Year 715,547 574,500 524,131 Non-controlling shareholders participation 1,379,751 1,409,169 1,675,314 Total Liabilities and Shareholders' Equity 25,376,778 25,984,477 26,304,568 1Q18 Results 17

Income Statement - Consolidated IFRS R$ thousand 1Q18 4Q17 1Q17 Change 1Q18/4Q17 Net Revenues 3,244,207 3,076,770 2,350,838 5% Domestic Market 2,646,153 2,499,518 2,109,663 6% Exports 598,054 577,252 241,175 4% COGS (2,632,109) (2,662,308) (1,870,099) -1% Gross Profit 612,098 414,462 480,739 48% Gross Margin 18.9% 13.5% 20.4% + 5.4 p.p. Operating Income (Expenses) (288,490) (343,831) (296,065) -16% Selling Expenses (76,138) (70,163) (52,193) 9% Provision for Doubtful Accounts (1,668) 3,261 (3,923) - Other Selling Expenses (74,470) (73,424) (48,270) 1% General and Administrative (102,782) (108,520) (93,141) -5% Other Operating Income (expenses) (109,570) (165,148) (150,731) -34% Reintegra Program 7,185 8,436 4,525-15% Provision for Contingencies (15,027) (28,834) (49,911) -48% Result of the Non Operating Asset Sale/Write-Off (6,797) (2,665) 1,408 155% Result of the Sale of the Surplus Electric Energy (13,596) 7,066 (22,701) - Temporary Equipments Shutdown (includes depreciation) (91,405) (91,250) (105,241) 0% Impairment of Assets - (74,892) - - Porto Sudeste Agreeement (net of expenses) - - - - Tax credit on imports PIS/COFINS 19,321 47,467 48,396-59% Other Operating Income (Expenses), Net (9,251) (30,476) (27,207) -70% EBIT 323,608 70,631 184,674 358% EBIT Margin 10.0% 2.3% 7.8% + 7.7 p.p. Financial Result (133,774) (172,084) (54,581) -22% Financial Income 76,894 105,297 159,151-27% Financial Expenses (185,187) (221,290) (269,349) -16% Net foreing exchange gain and losses (25,481) (56,091) 55,617-55% Equity in the Results of Associate and Subsidiary Companies 41,155 51,982 37,080-21% Operating Profit (Loss) 230,988 (49,471) 167,173 - Income Tax / Social Contribution (73,803) 4,620 (58,855) - Net Income (Loss) 157,185 (44,851) 108,318-450% Net Margin 4.9% -1.5% 4.6% + 6.4 p.p. Attributable: Shareholders 140,114 (49,918) 88,901 - Minority Shareholders 17,071 5,067 19,417 237% EBITDA (Instruction CVM 527) 621,866 372,950 528,095 67% EBITDA Margin (Instruction CVM 527) 19.2% 12.1% 22.5% + 7.1 p.p. Adjusted EBITDA - Joint Subsidiary Companies proportional EBITDA 641,202 450,378 532,769 42% Adjusted EBITDA Margin 19.8% 14.6% 22.7% + 5.2 p.p. Depreciation and Amortization 257,104 250,337 306,341 3% 1Q18 Results 18

Cash Flow - Consolidated IFRS Cash Flow - Consolidated IFRS 1Q18 4Q17 1Q17 Operating Activities Cash Flow Net Income (Loss) in the Period 157,185 (44,851) 108,318 Financial Expenses and Monetary Var. / Net Exchge Var. 49,781 119,187 4,178 Interest Expenses 99,100 125,102 192,519 Depreciation and Amortization 257,104 250,337 306,341 Losses/(gains) on Sale of Property, Plant and Equipment 6,797 2,665 (1,408) Equity in the Results of Subsidiaries/Associated Companies (41,154) (51,982) (37,080) Impairment of Assets - 74,892 - Difered Income Tax and Social Contribution 6,323 (166) 30,605 Constitution (reversal) of Provisions 111,030 39,359 73,428 Actuarial Gains and losses 8,694 7,273 7,273 Stock Option Plan - 2,198 295 Total 654,860 524,014 684,469 (Increase)/Decrease of Assets Accounts Receivables Customer (188,053) (222,373) (85,924) Inventories (241,758) 28,312 (253,094) Recovery of Taxes 40,170 (33,110) 2,125 Judicial Deposits (75,993) 20,475 (16,947) Accounts Receiv. Affiliated Companies 195 181 219 Others (26,854) (22,388) 25,957 Total (492,293) (228,903) (327,664) Increase /(Decrease) of Liabilities Suppliers, Contractors and Freights 130,378 238,660 (163,220) Amounts Owed to Affiliated Companies (8,917) 4,020 (23,086) Customers Advances 18,721 41,787 19,288 Tax Payable (64,649) 12,553 57,850 Securities Payable Forfaiting 52,102 273,917 249,782 Actuarial Liability Payments (34,343) (55,919) (59,582) Others 23,266 (113,920) (3,782) Total 116,558 401,098 77,250 Cash Generated from Operating Activities 279,125 696,209 434,055 Interest Paid (148,319) (147,170) (234,033) Income Tax and Social Contribution (17,672) (2,765) (14,760) Net Cash Generated from Operating Activities 113,134 546,274 185,262 Investments activities cash flow Marketable Securities 122,218 429,453 1,025,604 Fixed Asset Acquisition (61,629) (103,267) (22,674) Fixed Asset Sale Receipt 19,652 6,135 1,693 Dividends Received 128,013 23,261 1,274 Purchase of Software (3,238) - (3,793) - (683) - Net Cash Employed on Investments Activities 205,016 351,789 1,005,214 Financial Activities Cash Flow Payment of Loans, Financ. & Debent. (939,455) (293,496) (4,892) Payment of Taxes Installments (132) (3,321) (335) Swap Operations Liquidations - (2,886) (2,525) Net Cash Generated from (Employed on) Financial Activities (939,587) (299,703) (7,752) Exchange Variation on Cash and Cash Equivalents (8,084) 7,331 1,063 Net Increase (Decrease) of Cash and Cash Equivalents (629,521) 605,691 1,183,787 Cash and Cash Equivalents at the Beginning of the Period 1,770,573 1,164,882 719,870 Cash and Cash Equivalents at the End of The Period 1,141,052-1,770,573-1,903,657 - RECONCILIATION WITH BALANCE SHEET Cash and Cash Equivalents at the Beginning of the Period 1,770,573 1,164,882 719,870 Marketable Securities at the Beginning of the Period 543,715 973,168 1,537,584 Cash and Cash Equivalents at the Beginning of the Period 2,314,288 2,138,050 2,257,454 Net Increase (Decrease) of Cash and Cash Equivalentes (629,521) 605,691 1,183,787 Net Increase (Decrease) of Marketable Securities (122,218) (429,453) (1,025,604) Cash and Cash Equivalents at the End of the Period 1,141,052 1,770,573 1,903,657 Marketable Securities at the End of the Period 421,497 543,715 511,980 Cash and Cash Equivalents at the End of the Period 1,562,549 2,314,288 2,415,637 1Q18 Results 19