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Basic knowledge of metal materials (1)

Pig iron and steel are collectively referred to as ferrous metals. Iron is its main component and also contains a certain amount of carbon and other trace elements. Alloys with carbon content less than 2.11% (mass) are called steel, and alloys with carbon content greater than or equal to 2.11% (mass) are called pig iron.

metal-materials

Pig iron can be divided into pig iron for steelmaking (also known as white iron) and pig iron for casting.

Cast iron is referred to as cast iron. According to the shape characteristics of graphite, cast iron can be divided into the following categories: gray cast iron, codenamed HT; ductile cast iron, codenamed QT; corrosion-resistant cast iron; other cast irons, such as heat-resistant cast iron and malleable cast iron, Malleable cast iron is code-named KT, also known as malleable iron.

Cast iron pressure pipes and fittings are no longer mass-produced in the United States and other countries, but may be mass-produced in some countries. Ductile iron pressure pipes have replaced cast iron pressure pipes. Relevant standard specifications include: ASME B16.3, ASME B16.4, ASME B16.12, ASME B16.42, ASMEB16.42, ASTM A74, ASTM A126, AWWA C110, AWWA C111, AWWA C150, AWWA C153, etc.

Steel is essentially an alloy. The main component is iron and a small amount of carbon. It also contains trace elements such as silicon, manganese, phosphorus, sulfur, chromium, nickel, molybdenum, tungsten and vanadium. The classification of steel is shown in the figure

 

 

 

 

按照化学成分分类

 

 

碳素钢

普通碳素钢

 

 

优质碳素结构钢

低碳钢—c≤0.25%

中碳钢—0.25<c≤0.6%

高碳钢—c>0.6%

同时保证钢的化学成分和力学性能

 

一般S和P的质量分数均不超过0.04%

合金钢

低合金钢-合金元素总的质量分数一般小于5%

中合金钢-合金元素总的质量分数一般大于5%而小于或等于10%

高合金钢-合金元素总的质量分数一般大于10%

 

按照冶炼方法分类

平炉钢

转炉钢

电炉钢

坩炉钢

 

按照炉衬材料分类

按照冶炼脱氧程度分类

酸性钢

碱性钢

沸腾钢-不脱氧的钢
镇静钢-完全脱氧的钢
半镇静钢-半脱氧的钢

 

按照用途分类

普通钢

优质钢

高级优质钢-钢号后加“高”或“A”

 

按照赋予其形状的方法分类

铸钢

锻钢

轧压钢

冷拔钢

--本文摘自《压力管道设计及工程实例》第二版,主编:宋岢岢


Post time: Sep-07-2021