Method for surface overlaying of frame of continuous casting machine

Abstract

The invention discloses a method suitable for surface overlaying of a frame of a continuous casting machine, which comprises the steps of pretreatment before welding of the frame of the continuous casting machine for the processed welding assembly and surface overlaying of the frame, wherein the overlaying is gas shielded overlaying. The overlaying layer cladding alloy comprises the following components in percentage by weight(%): 0.02%-0.05% of C, 0.70%-1.10% of Mn, 0.20%-0.60% of Si, 16.0%-18.0% of Cr, S which is less than or equal to 0.025%, P which is less than or equal to 0.025% and the balance Fe and inevitable impurities. The invention has the characteristics of advanced method, high production efficiency, low welding cost and the like, the overlaying layer has good corrosion resistance and wear resistance, and the frame can be integrally tempered to relieve stress after overlaying.

Description

technical field [0001] The invention relates to a method for surfacing welding on the surface of a continuous casting machine frame, which belongs to the welding technology of heavy mechanical components. Background technique [0002] The continuous casting machine involved in the present invention is an important equipment for furnace continuous casting in iron and steel enterprises, and the continuous casting machine frame is a large component used to carry multi-stage rolls and their transmission devices. [0003] With the substantial increase in production capacity of iron and steel enterprises, continuous casting equipment has been widely used. In order to improve the service life of the frame, many manufacturers adopt the method of surfacing stainless steel on the block surface of the bearing block assembled with the roll when designing the frame of the continuous casting machine to improve the block surface of the bearing block. Excellent corrosion resistance, high t...

AI Technical Summary

Problems solved by technology

Since the frame of the continuous casting machine works at a temperature of 500-550°C for a long time, and the A302 surfacing layer is an austenite structure containing 0.15% C and 21% Cr, the excess C continuously transfers to the austenite grains. Boundary migration and diffusion, and combined with Cr to form chromium carbide compounds in the intergranular, such as (CrFe)23C6, etc., precipitated, resulting in a chromium-depleted layer (Cr<12%) at the austenite grain boundary, thus under the action of the corrosive medium Intergranular corrosion occurs under the environment, which eventually leads to corrosion and cracking of the surfacing layer, causing the surfacing layer to break, collapse or even fail

[0006] 2. The surfacing layer cannot be tempered to relieve stress

But because the surfacing layer of prior art is medium carbon austenitic structure, do not allow to implement tempering treatment (tempering can produce intergranular corrosion and 475 degree embrittlement), thereby can only directly process after surfacing, make The stress of the frame cannot be eliminated, so its dimensional stability is poor, and the machining accuracy is difficult to guarantee

[0007] 3. Poor wear resistance

But the hardness of A302 (Austria 302) surfacing layer of prior art is in the range of 140~160HB, and its overall wear resistance is poor, thereby can not satisfy the wear resistance requirement of described frame

[0008] 4. Low production efficiency and high welding cost

Because what prior art adopts is manual arc welding surfacing welding method, its production efficiency is only 30~40% of gas shielded welding, and it adopts the deposited metal recovery rate of electrode welding to be only about 60%, and gas shielded welding The yield of welded deposited metal reaches more than 90%