Fiber Elongation

[Mec.tec]

A dishend is made using hot forming. The material is SA 516 Gr 70 normalized, thickness is 30 mm and fiber elongation exceeds 5 % . Is pwht and mechanical testing required?
Construction code is ASME SEC VIII-1.

 

[david339933]

Post Formed Heat treatment is only necessary when cold formed. See UCS-79 (d) "..fabricated by cold forming..".

 

[metengr]

What was the temperature of hot forming? Warm Forming can be as high as 900 deg F (see UCS-75 (d) 5.)

 

[Mec.tec]

The forming temperature is 420 deg C.please also guide for testing as recommended by material specification.i have a confusion regarding plate heat treated condition like what would be the case when plate is normalized and what would be the case when it is not normalized .

 

[metengr]

As I suspected, this is not hot forming. Since the forming was performed below 480 deg C, this would default to a post forming thermal treatment to remove the effects of strain because the fiber elongation exceeded 5%.

The above applies for normalized or as-formed plates. Read the entire UCS-75.

 

[Don56]

metengr I think you mean UCS-79(d)(5).

 

[Mec.tec]

Thanks metengr, can you please tell me what is the range of temperature where we consider it hot forming?
Also let me know what are the requirements after hot forming and where they are addressed?

 

[metengr]

Typically, any forming performed at or above the lower critical transformation temperature is considered hot forming. Normally this temperature range can be as low as 1350 deg F to as high as 1900 deg F.

Directly after hot forming, you can either air cool the steel (as hot formed condition) or hold the steel at 1650 deg F or higher temperature to ensure complete austenitization, air cool, which would result in a normalization heat treatment or you could quench and temper. You have options.