I find this welder’s certificate a bit hard to understand
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GTAW-FeⅡ-5G-2/20-FefS-02/10/12+ SMAW-FeIV-5G(K)-4/20-Fef4 As stated in the question, is the test specimen a composite material?
I checked the **Quality Supervision Bureau’s website, and it’s indeed the case
I don’t quite understand it either. It’s probably a project certification for the argon-electric welding of bimetallic composite corrosion-resistant steel pipes. I checked the GB/T17395-2008 standard, which covers pipes with a diameter of φ20×6; I also checked the GB/T31940-2015 standard for bimetallic composite corrosion-resistant steel pipes used in fluid transportation. I guess there are pipes of this type, φ20×6 – with 2 mm of stainless steel inside and 4 mm of carbon steel on the outside. But such examination items are indeed rare! ! ! ! But there’s a problem with the way this project is presented! ! I think it should be: GTAW-FeⅣ-5G-2/20-Fefs-02/11/12+SMAW-FeⅡ-5G(K)-6/20-Fef4. The meaning of this designation is a double-metal composite corrosion-resistant steel pipe with dimensions of φ20×6. The base weld is made using manual TIG welding on stainless steel, with a thickness of 2 mm; the carbon steel portion is filled and covered using SMAW with stainless steel electrodes, resulting in a weld thickness of 4 mm. This is my personal understanding; please discuss it! !
That makes sense; could the certificate be wrong?
The metal material category of the pipe material cannot be written incorrectly, but other category codes for filler materials can be used! For details, see Page 38 of TSG Z6002-2010 on the notation method for examination items.
For double-metal composite corrosion-resistant steel pipes like this, welding should be carried out using the following procedure codes: GTAW-FeⅣ-5G-2/20-Fefs+SMAW-FeⅣ-5G-6/20-Fef4, as the procedure codes for stainless steel also apply to welding stainless steel with other carbon steels of lower grade numbers. Personal opinion! !