4130 with SS E316L-17 Overlay without PWHT? 2

[KnaT]

Hi Guys,

We are planning to qualify an Overlay welding procedure for:
AISI 4130
Forged Block cut to 1 inch thk. plate,
75 Ksi min. YS and 95 Ksi min. TS,
C 0.3%, Cr. 0.99%, Mn 0.52% and Mo 0.17%
with following Heat Treatment done by mill: Normalizing - 900 Deg. C, 9 hours, Quenching in Water - 880 Deg. C, 9.0 hours, Tempering - 665 Deg. C, 16 hours)
Overlay welding: SMAW Process using E316L-17 Electrodes (2.4mm and 3.2mm).
Keeping a min preheat temperature of 150 Deg. C and an interpass temperature of 200 Deg. C.
Heating the test coupon to 250-300 Deg. C for 30 mins. after welding and allowing it to cool slowly in wrapped condition. No other PWHT to be performed.

Do you think this Test Coupon will qualify the mechanical Testing? Any suggestions regarding these temperatures or controlling the Heat Inputs will be much appreciated.

 

[metengr]

KnaT;

SMAW Process using E316L-17 Electrodes (2.4mm and 3.2mm).

You need to overlay first with E309MoL-16 - 2 passes
The remaining passes should be E316L-17

Keeping a min preheat temperature of 150 Deg. C and an interpass temperature of 200 Deg. C.

I would increase the preheat to 175 deg C minimum and the interpass to 250 deg C.

Heating the test coupon to 250-300 Deg. C for 30 mins.

. OK

after welding and allowing it to cool slowly in wrapped condition. No other PWHT to be performed.

 

[jbeckhou]

IF you are following API and NACE, PWHT is required.

Petrotrim Services

http://www.petrotrim.com

 

[metengr]

You will need to perform hardness testing, which will determine compliance with NACE. The mechanical properties part of the WPS qualification (tensile and bend testing) should pass, hardness testing of the base metal HAZ is questionable.

 

[KnaT]

jbeckhou - I did not see a specific clause in API 6A stating that PWHT was mandatory. It just says that it should be as per WPS. I understand that it is recommended for 4130 but if we can qualify a WPS with the desired mechanical properties shouldn't that suffice our purpose? Even without PWHT I am achieving a hardness of around 220 HB which I believe is within the NACE Requirements.

metengr - May I know the reason for the suggested Pre-heat and Interpass Temperatures?

Coming to your concern for Dilution, I consulted API 6A on that as well. It defines a chemical composition 3 mm above the base metal for overlay welding which is Ni 8% min, Cr 16% min, C 0.08% max. I have seen similar qualifications before in which Chemical Analysis passed this criteria. So, lets hope for the best.

 

[jbeckhou]

KnaT
See section (6.5) 6.5.1.1.3 API-6A 20th ed.

Section that is over looked most of the time, 6.5.2.4

It is important to note that the weld and base metal HAZs contain residual stresses and may contain hard and brittle transformation products that have not been tempered by the heat of welding. If residual stress and hardness in these areas are not sufficiently reduced, the weldment will be susceptible to sulfide stress cracking and hydrogen embrittlement and will not meet NACE MR0175.


Petrotrim Services

http://www.petrotrim.com

 

[metengr]

metengr - May I know the reason for the suggested Pre-heat and Interpass Temperatures?

Yes, it is called past experience.

 

[786392]

Dear metengr, Hello/Good Morning,

I like that!!

Best Regards
Qalander(Chem)

 

[KnaT]

Metengr I got the hardness test results of the PQR. Hardness values in the HAZ are ranging from HV 301 to 246 (Avg. HV 271).

 

[metengr]

Too high, this is why hardness testing is required. Given the hardness data, you need to butter with the E309MoL-16, PWHT, and follow it up with the remaining passes for the CRO.