Surface treatment process for spherulitic graphite cast pipe

Abstract

The invention relates to a surface treatment process for a spherulitic graphite cast pipe, which comprises a surface pore-filling step and a pore-filling material sintering step, wherein the surface pore-filling step is carried out before a heat treatment process of spherulitic graphite cast pipe production, the pore-filling material sintering step is carried out in the heat treatment process, in the surface pore-filling step, the pore-filling material is selected according to the highest holding temperature in the heat treatment system so as to ensure that the highest holding temperature in the heat treatment system is within the sintering temperature range of the pore-filling material, and the pore-filling material is coated on the local surface of the spherulitic graphite cast pipe through a binder before heat treatment. The heat treatment is one or more of normalizing, annealing and modulating. According to the process, the pore-filling sintering process is subjected to step decomposition, and the pore-filling material sintering step is carried out in the heat treatment process, so that the problems of energy waste, high operation difficulty and poor treatment effect of the traditional pore-filling process are solved, and the selection of the pore-filling material and the adjustment of the sintering characteristics are convenient and flexible.

Description

technical field [0001] The invention relates to the field of casting production of ductile graphite pipes, and more particularly, relates to a surface treatment process after casting of ductile graphite pipes. Background technique [0002] Ductile cast pipe is a common water supply and delivery pipe in engineering. As a large-scale casting, it is a common problem in the casting process that the roughness size is out of tolerance due to the large surface holes and the subsequent poor coating. [0003] At present, hole-filling and sintering is often used in production to deal with the problem of large local pores in ductile graphite pipes. Due to the large size of ductile graphite pipes, the hole-filling and sintering operation cannot directly place the entire casting on the surface after filling the surface holes with metal powder like ordinary castings. The metal powder is sintered in the heating furnace, but only by means of gas or a special electric heating coil to heat th...

AI Technical Summary

Problems solved by technology

[0005] In order to solve the three problems mentioned above in the background technology, the present invention provides a surface treatment process for ductile cast pipes, which decomposes the existing hole-filling and sintering process as a surface post-treatment means and integrates it into the normal heat treatment of ductile cast pipes In the process, the three major problems of energy waste, difficult operation and poor treatment effect are completely solved