Method for repairing core rods for rolling seamless steel pipes

Abstract

The invention discloses a method for repairing core rods for rolling seamless steel pipes. The method comprises the following specific steps: (1), cleaning and detecting before repairing; (2), machining before repairing; (3), detecting before surfacing; (4), surfacing and preheating; (5), surfacing to recover the size; (6), carrying out heat treatment after surfacing; (7), machining after surfacing; (8), detecting before laser cladding; (9), carrying out high-speed laser cladding by carrying out strengthening treatment on the surfaces of core rods by adopting high-speed laser cladding, wherein the used powder material is alloy powder with excellent wear resistance, corrosion resistance and plasticity and toughness; (10), machining after cladding; and (11), detecting finished products. According to the method, the wear resistance, the corrosion resistance and the cold and hot fatigue resistance of the core rods can be greatly improved; the service life of the core rods reaches more than 1.5 times of that of a new product; meanwhile, the whole repairing and manufacturing process is green and pollution-free.

Description

technical field [0001] The invention relates to the field of mandrel repair methods, in particular to a repair method for mandrels for rolling seamless steel pipes. Background technique [0002] The mandrel is a hot deformation tool for rolling seamless steel pipes in the continuous rolling mill, and is mainly used to perforate the billet at high temperature. The working conditions of the mandrel are extremely complex and harsh: the temperature of the hot-rolled mandrel is high during rolling, and it must bear high axial tensile stress and radial compressive stress; the mandrel is in an unstable temperature field during use. Among them, the service temperature is as high as 1150°C, and the surface temperature rises to 700°C, and it is water-cooled after use to withstand alternating cycles of cold and heat and thermal wear. Therefore, the main failure mode of the mandrel is local cracks and excessive wear. When the mandrel fails, in order to save costs, the mandrel is gener...

AI Technical Summary

Problems solved by technology

[0003] At present, the repair process of the mandrel usually adopts the method of "surfacing + electroplating", which mainly has the following shortcomings: 1. The surfacing process is poor. High preheating temperature will cause the mandrel to deform; at the same time, the surfacing layer has poor thermal fatigue resistance and is prone to cracks; 2. The electroplating layer has low bonding strength and is easy to peel off

Therefore the life-span of the mandrel that this kind of method obtains is shorter, can only reach about 80% of new product

At the same time, the electroplating process is highly polluting and does not meet the national green manufacturing requirements