Causes of Effect Factors Elements Alloy Pattern Type and Crystallization Temperature; Alloying Elements; Mechanical Elements Affecting Factors (2) Cold Cracking Causes: Welding thermal cycle (joint exists hardened microstructures), welding stress, and dispersed hydrogen generation cause factors : Hardening tendency (M, lattice distortion), Hydrogen induced cracking (delayed crack), Restraint stress influencing factors (3) Brittle fracture: ) Brittle fracture: Cause of occurrence: Cause of occurrence: Joint brittle, hard brittle, non-metallic inclusions , Aging embrittlement, cold work hardening influencing factors: metallurgical response, thermal cycle, crystallization influence factors (4) application function: ) application function: mechanical function: mechanical function: strength, plasticity, toughness, special function: corrosion, high temperature impact toughness, High-temperature creep strength, layered tearing of thick steel plates, and stress corrosion of low-alloy steels Special function 4. Solderability test methods: Solderability test methods: (1) Carbon equivalent method) Carbon equivalent method: Content of alloying elements in steel Equivalent to a number of carbon contents converted and superimposed as a rough assessment of cold cracking of steel Parameters of the object, i.e., a so-called carbon equivalent (CE or Ceq).