Material Equivalent to ZG20SiMn

[Abu Bakar]

Hello,

I am currently in the middle of a project where I will need to weld a twistlock to my foundation beam. The beam is in S355JR grade, but I just found out today that the twistlock bracket is of a material ZG20SiMn, which I am very unfamiliar of. From my online research, I found out it is from China GB/T standard, hence not really common grade used worldwide.

My welding procedure is not covering this material, before I go to the extent of considering to qualify new welding procedure, I would like to know more about the material in term of it's chemical properties, mechanical properties, general application, it's equivalent to more common standard (EN/ABS/ASTM/DNV), etc.

Would appreciate a lot any insight regarding this material, or at least the reference that I can refer to.

 

[mrfailure]

What do you mean? There is plenty of information on material properties when you Google this, including the Europeon equivalent G20Mn5 (1.6220)

 

[casting supplier]

yes, Mr failure is right about the material ,

Pike Li
uxitech.net

 

[Gavinluoy]

ZG20SiMn is a low-alloy cast steel with high sensitivity to hydrogen-induced cracking. Due to the thickness of the base material, there is a relatively high level of constraint and susceptibility to cold cracking. Therefore, when selecting welding materials, it is advisable to prioritize the use of ultra-low hydrogen welding materials to enhance crack resistance and reduce preheating temperatures.

1. Selection of Submerged Arc Automatic Welding Materials
For submerged arc automatic welding, both the wire and flux directly participate in the metallurgical reactions during welding. Their chemical composition and physical properties affect the welding process, influencing the chemical composition, structure, and properties of the weld metal. Using suitable welding wire and flux can achieve moderate fusion of the base material, thereby improving the strength of the weld. The welding wire H10Mn2 has good compatibility with ZG20SiMn, with high alloy element content, effectively refining the grain structure and enhancing the weld's plasticity and toughness. The flux, selected to match the welding wire H10Mn2, is the sintered flux SJ101, which is lightweight, consumes less during welding, and does not significantly increase Si and Mn in the weld metal. It is metallurgically neutral, exhibiting excellent welding process performance, stable arc combustion, easy slag removal, aesthetically pleasing weld formation, and high low-temperature impact toughness. The flux should be baked at 300-350°C for 2 hours before use.

2. Selection of CO[sub]2[/sub] Gas Shielded Welding Materials
CO[sub]2[/sub] gas-shielded welding uses both solid wire and flux-cored wire for welding. The wire serves as both the filler metal and the conductive electrode. The chemical composition of the wire, in coordination with the shielding gas, affects the chemical composition of the weld metal, which in turn determines the chemical and mechanical properties of the weld. The flux-cored wire contains flux or a mixture of metal powders inside, promoting metallurgical reactions between the molten core material, base metal, and shielding gas during welding. It forms a thin layer of liquid slag covering the molten droplets and weld pool, protecting the molten metal. E501T-1 flux-cored wire is recommended for achieving optimal weld quality. The purity of the selected shielding gas (pure CO[sub]2[/sub]) should be greater than 99.9%.

3. Selection of Welding Parameters

4. Preheating before welding, heat treatment after welding
The temperature of the welding area reaches 150-200°C and reaches this temperature throughout the welding process；
After welding is completed, the inside of the workpiece
A large amount of welding residual stress is generated. To prevent delayed cracks and deformation during processing, Shape and annealing treatment should be carried out promptly after welding.
The annealing temperature should be controlled at 520-560C. The heat treatment curve is shown in the figure.

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