When carbon is added to iron in proper _________ the result is steel.
举一反三
- When<br/>carbon is added to iron in proper __________, the result is<br/>steel. A: rates B: thicknesses C: proportions D: densities
- How does steel differ from pig iron? A: Less carbon B: More carbon C: Steel is preferred by sheep and chooks D: None of the above
- According to the passage, how did Bessemer method make the mass production of steel possible A: It directed air at melted iron in a furnace, removing all impurities. B: It slowly heated iron ore then stirred it and heated it again. C: It changed iron ore into iron which was a substitute for steel. D: It could quickly find deposits of iron ore under the ground.
- High-speed steel is also___________________(know) as self-hardening steel.
- The main social services of the iron and steel industry system are the provision of iron and steel products and the consumption of iron ore A: 正确 B: 错误