hot-rolled steel, grain size/HV requirements are appropriate or not?

[fusitexa]

hello all,

recently, we want to use hot-rolled plain carbon steel and we list grain size and HV requirements in spec. however, the steel supplier said they couldn't provide this information, the reason they gave is"so many years, for acid pickle coil steel, there is no any customer to list this kind of requirement''. could anyone tell me the supplier's answer is right, and our requirements make sense or not? thanks in advance and look for your reply.

Oliver

 

[metengr]

There is no right answer. The Supplier provided you with an answer to your inquiry that basically means he cannot do this supplemental testing and meet your purchase specification. So, either have the grain size and hardness testing performed by an independent lab or find yourself another supplier that can provide this information for their product line.

Why do you require grain size and hardness for hot rolled carbon steel?

 

[fusitexa]

metengr,

thanks for your reply.
for grain size requirement, because we find that if the grain size is larger than, such as ASTM No.7, the failure rate is high. so we try to spec. grain size and to improve quality and it was proved right. for hardness, it is easy to do and routinely tested in our lab. while we have no tensile machine in lab.

BR

 

[stanweld]

fusitexa,
You will need to find another supplier who is willing to meet your requirements, which can be met with proper melting practice, finish rolling parameters and coilng temperature. You might want to specify one of the vanadium/niobium micro-alloyed strip grades.