are very soft ,and can be used for bolts and for machine parts that do not need strength.: Alloy steels|High carbon steels|Low carbon steels|Medium carbon steels

For low carbon steels, the Hooke's law σ=Eε is applicable when the unidirectional tensile stress is not greater than ___.

HTLA steels are susceptible to reheat cracking because they are with a lot of (). A: carbides B: hydrogen C: sulphur D: manganese

HTLA steels are susceptible to reheat cracking because they contain a lot of () A: carbides B: H C: S D: P

( ) cracking is generally encountered during postweld heat treatment (PWHT) of steels A: Reheat B: Stress relief C: Hydrogen induced D: Solidification

HTLA steels are susceptible to reheat cracking because they contain a lot of () A: carbides B: H C: S D: P E: 2-3-2 F: 期末

The common heat treatment on steels such as 65Mn and 60Si2Mn is . A: quenching + low temperature tempering B: quenching + medium temperature tempering C: quenching + high temperature tempering D: normalizing

中国大学MOOC: 现代肉鸡业起源于美国Delmarva半岛。在20世纪20年代，特拉州的Steels夫妇开始经营专门的肉用仔鸡。

现代肉鸡业起源于美国Delmarva半岛。在20世纪20年代，特拉州的Steels夫妇开始经营专门的肉用仔鸡。 A: 正确 B: 错误