advice needed for welding Hardox 700

admin

Currently I'm using ESAB t-115 to weld on Hardox 700. Problem facing: When the weld cool down, hair line crack start to appear on the weld. What is happening that cause the crack to appear. Due to wire? Gas?
Reply:The most likely cause is not enough pre-heat, not a slow enough cool down.Where I work we weld a lot of HardOx 500. It is always pre-heated to 300 deg. Interpass temp not to exceed 475-500 deg.When we can, we cover with weld blankets after welding to slow the cooling rate.Depending on what the application is, we either weld with er70 hard wire or 309L stainless.If the proper pre-heat, cool down process is used, we have very little cracking. Usually non at all.Will