In general, 304L SS and 316L SS are readily weldable with common arc processes such as; GTAW, SMAW, GMAW processes and other techniques. These traditional arc processes produce moderate rates of heat input with correspondingly moderate cooling and solidification rates and will generally produce a crack free weldment with acceptable microstructure in typical heats of 304L SS and 316L SS.

The susceptibility of austenitic stainless steels to solidification cracking and lack of penetration, two distinct weld characteristics related to the chemical composition of the base material is reviewed. The propensity for cracking is determined primarily by the solidification mode and the amount of residual tramp elements such as phosphorous and sulfur. High sulfur levels can lead to weld centerline cracking and HAZ cracking while very low sulfur levels (less than ~50 ppm) in 304L SS and 316L SS are associated with lack of penetration weld defects and a distinct loss in puddle control during fusion welding. A calculated Creq./Nieq. ratio of 1.52 to 1.9 is recommended to control the primary mode of solidification and prevent solidification cracks in 304L SS while the Creq./Nieq. ratio of 1.42 to 1.9 is recommended for 316L SS. A lower limit of 50 ppm sulfur is recommended to avoid possible lack of penetration.

Meanwhile there are some restrictions of specific welding processes. For example about corrosion resistance degradation of Ni alloys, (1) carbon pickup from the flame in oxyacetylene welding [not recommended], (2) chromium loss across the arc and silicon pickup from the welding flux because of the high heat input of SAW [not recommended unless otherwise controlled].

In your question for solidification crack, the only concern is the some effect of SMAW flux (e.g., factors to interrupt the solubility of S & P in ferritic structure), however I do not have seen that kind of effect so far.

Please let me know where the information comes from.

thomaseun@hanmail.net

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스테인레스 용접시 고온균열을 방지하기 위한 방안중 4번 항목이 이해가 잘 되지 않습니다.
제생각으로는 피복제의 사용과 SMAW가 GTAW 보다는 입열이 높아서라고 생각하는데 이것이 맞나요?

1. 일정량의 델타 페라이트 함유
2. 입열을 낮게
3. 가능한 구속도는 적게
4. SMAW 보다는 GTAW로 용접