To counter this, preheating of base metal could reduce the different thermal expansion coefficient which will affected cooling rate of weld metal. Residual tensile stress could cause crack to propagate without any applied stress. Preheating of base material also one of the techniques to relesare hydrogen from working object. In the case of welding filler (especially SMAW) has been exposed to the atmosphere, proper baking of electrode is recommended to eliminate moisture from flux. Hydrogen content can be reduced by using hydrogen free consumable. The amount of hydrogen (H2) dissolved in weld metalĭissolved hydrogen in weld metal is related to hydrogen embrittlement.Factors that can contribute to the occurrence of cold crack are: Also this crack mechanism could propagate both between grains and through grains. However, for other alloy steel with high degree of hardenability, cold cracking could occurs in both weld metal and HAZ.

This type of crack usually observed in HAZ especially for carbon steel which has limited hardenability. That is why some code require testing on welding work object 48 hours after the welding process. ( August 2022) ( Learn how and when to remove this template message)Ĭold cracking which also known as delayed cracking, Hydrogen Assisted Cracking (HAC) or Hydrogen Induced Cracking (HIC) is type of defect that often develop after solidification of the weld, when the temperature starts to drop from about 190 ☌ (375 ☏) but the phenomenon often arises at room temperature, and even more, and it can take up to 24 hours after complete cooling.

Welding defects causes and remedies pdf