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图1为瓦工用砌砖刀的简图。所用材料是65Mn合金钢。其技术要求如下:刀体热处理后硬度HRA72—78;长度方向翘曲≯1 MM;连续三次弯曲30°后能恢复原状。刀体厚度1.4MM—1.6MM,长度分别为180MM、200MM和220MM三种规格。该砌砖刀属于典型的长而薄的另件,几年来热处理变形问题一直没有得到解决。原工艺过程为:下料→焊把→热处理→磨削→上油包装。热处理工艺为:850℃加热油淬,280—?00℃硝盐回火。因原工艺过程为焊把后再行热处理,淬火加热装夹具时(小头朝下,有把端朝上),很难保证垂直,特别是焊把后局部存有一定应力,因而淬火后变形量很大。虽经及时校正,但合格率仅达30％左右,致使40％的产品无法校正而报废。由于返修率高,造成
Figure 1 bricklayer tile brick diagram. The material used is 65Mn alloy steel. The technical requirements are as follows: Tool body hardness HRA72-78 after heat treatment; warp length direction ≯ 1 MM; after three consecutive bending 30 ° to restore the status quo. Body thickness 1.4MM-1.6MM, the length of 180MM, 200MM and 220MM three specifications. The brick cutter is a typical long and thin pieces, the heat deformation problems over the years has not been resolved. The original process is: blanking → welding → heat treatment → grinding → oil packaging. Heat treatment process: 850 ℃ heating oil quenching, 280-? 00 ℃ nitrate salt tempering. Due to the original process for the welding rod after heat treatment, quenching heating fixture (small head down, with the end up), it is difficult to ensure vertical, especially after the local welding there is a certain stress, and thus the amount of deformation after quenching Great. Although timely correction, but the pass rate of only 30%, resulting in 40% of the products can not be corrected and scrapped. Due to the high repair rate