WHEN TO POST WELD HEAT TREAT #15
Inside weight hardware benchmarks, the necessity for post-weld heat treatment is to a great extent a component of the material and the thickness. The material (as far as combination content) and the thickness (according to the extinguishing impact) control the microstructure that will be framed. Enormous segment thicknesses in compound steels can result in martensitic, pearlitic or bainitic structures, contingent upon the cooling rate, and this is generally constrained by the utilization of preheating. Also, the thicker the material that is welded, the more noteworthy the measure of lingering pressure that will be created on cooling.
For the run of the mill carbon-manganese steels, the thickness at which post-weld heat treatment becomes compulsory is predictable in the 32 – 38 mm go for the greater part of the Codes being used in Australia. The explanation behind every standard picking a particular thickness isn’t totally clear, yet little has changed in the course of recent years. What is fascinating however is that tests led in the mid-1970s indicated that completely limited butt welds in carbon-manganese steels could create remaining worries in the overabundance of the yield pressure at a thickness of around 35 mm.
With composite steels, the thickness at which post-weld heat treatment becomes obligatory is significantly less. Regularly, the range is 13 – 20 mm, and even underneath 13 mm, a progression of severe conditions must be met before post-weld heat treatment can be deferred. It is clear hence, that with composite steels, the removal of remaining pressure isn’t the main thought for the use of post-weld heat treatment.
Post weld heat treatment of auxiliary steels is practically unbelievable. Indeed, even in the seaward industry, the Nodes and K-joints on the jackets are never again post-weld heat treated. At the point when that industry was in its earliest stages, post-weld heat treatment was compulsory and was applied, however next to no CTOD data was accessible at that point, and the materials being used endured laminar tearing. That has all changed now, and not many joints require any consideration today. Additionally, the gigantic machines being used in the mining business are not exposed to post-weld heat treatment, and it isn’t tended to in the scope of basic welding measures, AS 1554 sections 1 to 6. Thusly, the point is basically restricted to the weight hardware industry. continue………..
Subscribe to the newsletter news
We hate SPAM and promise to keep your email address safe