Development of Manufacturing Process for High-Chromium Steel Large Welding Roll

Due to the operating conditions of weld and calibrating rolls used in the production processes of large electric-welded pipes, their material is subject to stringent wear and abrasion resistance requirements at high temperatures. The limited capabilities of conventional Cr-Mn-Ni tool steels and open die forging technologies with heat treatment processes do not provide the required performance properties for large welded rolls. Therefore, the material of the product was replaced with Cr12MoV high-chromium steel. This required identifying the formation patterns of the fine grain structure of high-chromium steel in order to adjust the production technology with adaptation to the unique conditions and equipment (12.5 MN hydraulic forging press, heating and thermal furnaces) of the forging shop. The technology was offered, which included the development of modes from heating to heat treatment with intermediate two-stage forging from Cr12MoV steel ingots in two sets of combined dies. At the first stage, deformation with a low reduction ratio ε = 5% and a relative feed rate of 0.4 per pass was provided to break and refine the carbide mesh, and at the second stage, intense deformation with a reduction ratio ε = 15% was performed. Further practical application has shown that the durability of weld rolls made from the new material increases by 20–30%.