Transverse crack weld in weld metal solidification crystallization process produces. Solidification, low melting point eutectic enrichment at the grain boundaries, a “liquid film”, due to the weld solidification shrinkage by tensile stress, eventually cracking the formation of cracks, also called crystal cracks. Produced between the internal weld two columnar crystals along the transverse weld cracking, a transverse crack.
Measures to avoid transverse cracks are:
1, Select the appropriate welding material
Select the appropriate welding materials, helps to reduce the content of harmful elements in the weld, the weld center to reduce the impact of low-melting substance.
2, To improve the welding process
a) In the case of guaranteed depth of penetration is reduced within the weld groove, reduce internal weld specifications, while increasing the outer groove weld and increased external welding specifications.
b) Automatic tracking welding tracking and watching the “red line” a combination of methods to increase the size of a large wall thickness of the steel sheet to be blunt edge and bevel angle, increasing the variety of specifications cutter, change the groove of the actual situation blunt edge angle and size.
3 The use of appropriate weld coefficient
General requirements for weld coefficient (B / H)> 1, to ensure that no cracks in the welding process. In the actual production process, such as the wall thickness of steel pipe welds typically 12.5mm width of 15-16mm, a depth of 6-7mm, form factor 2.1-2.7. By increasing production outside the weld groove, control form factor close to 2, the possibility of cracks can be greatly reduced.
4, Precise tone type
Steel molding quality will directly affect the subsequent welding quality by accurate tone patterns, reduce the residual stress of the weld, can reduce the chance of transverse cracks.
Post time: Sep-10-2019