PWHT ASTM516 Gr 60 and SS316L 1

[cardiff10]

Please can anyone let me know the heating rate to be used for PWHT of ASTM 516 Gr 60 and SS316L

Is there a fixed rate of heating for all thicknesses?

For carbon steel A516 Gr60 we are working with all thicknesses up to 60mm.

Thanks for your help.

 

[metengr]

cardiff10;
You will find requirements for heating and cooling based on the applicable code of construction.

 

[cardiff10]

The applicable code is ASME Section VIII Div 1.

I have looked at this section and found a rate of 222 deg C/Hr advised which shall be divided by the maximum thickness of the shell or head.

Does this mean for 1 inch thick shell the heating rate can be 222deg C/Hr? Is this normally practiced?
Please advise, your help is much appreciated.

 

[Duwe6]

It is NEVER practiced by prudent Heat Treaters. This is a Maximum, not a nominal. If your HT chart shows that a 225°C/hr rate was used, it is a "Fail", and requires a Non-Conformance investigation and documentation.

With an absolute max of 222°C, I would use about 180°C/hr per inch thickness. That way, an error of 10% too fast will still leave me comfortably in the "Acceptable" zone.

 

[cardiff10]

Thanks DUWE6 for your help, Just to double check
for 2 inch thick material the safe heating rate would be
about 110 deg C/Hr according to the same code?

Thanks in advance.

 

[Duwe6]

The MAX rate for 2-inch material would be 111°C/hour. The *safe* rate would be 90°C/hr.

 

[Guest102023]

Good advice already given, but in practice it is often difficult or impossible to hit the maximum rates. This is one of those areas where 'engineering judgment' comes in, e.g., if the fabrication is complex. Dissimilar metals (CTExp) is a complicating factor.

 

[Duwe6]

Trust me, I have hit 600°F per hour, personally. Not one of my better afternoons.