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一、滾道使用中焊縫開裂問題的分析
1、 Analysis of weld cracking in raceway
混凝土攪拌車滾道在使用中常出現焊縫開裂的問題。究其原因，主要有以下幾個方面：
The problem of weld cracking often occurs in the raceway of concrete mixer. The main reasons are as follows:
1.滾道與罐體分別采用不同的材料，含碳量相差較大，且焊后未進行熱處理，導致在靠近滾道一側出現裂縫。方法：更換滾道材質。例如，當罐體采用Q345板材時，滾道也相應采用Q345材料。這樣，滾道與罐體材料一樣，焊接性能較好。
1. The raceway and tank body are made of different materials, the carbon content varies greatly, and no heat treatment is carried out after welding, resulting in cracks on the side close to the raceway. Solution: replace the raceway material. For example, when the can body adopts Q345 plate, the raceway also adopts Q345 material accordingly. In this way, the raceway is the same as the tank material, and the welding performance is better.
2.滾道截面的徑向高度尺寸小、撓度小，或者攪拌罐的剛度低，在使用過程中易產生彈性變形，使罐體與滾道的焊縫連續(xù)承受交變應力，導致開裂。裂縫在靠近罐體后部的一側。方法：增大混凝土攪拌車滾道截面的徑向高度。
2. The radial height dimension of the raceway section is small, the deflection is small, or the stiffness of the mixing tank is low, which is easy to produce elastic deformation during use, so that the weld between the tank body and the raceway can continuously bear alternating stress, resulting in cracking. The crack is on the side near the rear of the can body. Solution: increase the radial height of the raceway section of the concrete mixer.

3.滾道和罐筒材料厚度相差極大，焊接工藝控制不好，容易導致焊縫或罐體開裂。例如，當焊接電流過大時，罐筒處就會形成咬邊現象，容易導致罐皮開裂；或者當焊縫焊偏時，滾道和罐體的熔合面過大或過小，受力不均導致焊縫開裂或罐體開裂。方法：控制好焊接時的焊接形式、工藝參數和焊接位置，較好采用埋弧焊接工藝。
3. The material thickness of raceway and tank barrel varies greatly, and the welding process is not well controlled, which is easy to lead to weld or tank cracking. For example, when the welding current is too large, undercut will be formed at the tank barrel, which is easy to cause cracking of the tank skin; Or when the welding seam is biased, the fusion surface between the raceway and the tank body is too large or too small, and the stress is uneven, resulting in weld cracking or tank cracking. Solution: control the welding form, process parameters and welding position during welding, and better adopt submerged arc welding process.
二、滾道的加強方案
2、 Strengthening scheme of raceway
除了以上幾種混凝土攪拌車滾道焊縫開裂的常規(guī)方法以外，我們還可以從另一個方面考慮，就是對混凝土攪拌車滾道與罐筒的焊接處進行加強。即：在罐筒內壁上增加加強環(huán)能夠有效提高滾道處罐體強度和剛度，有效分散滾道處罐體的集中載荷，提高罐體的承載能力，減少罐體與滾道連接處焊縫開焊及滾道處罐皮開裂事故。
In addition to the above conventional methods to solve the weld cracking of concrete mixer raceway, we can also consider from another aspect, that is, strengthening the weld between concrete mixer raceway and tank barrel. That is, adding a reinforcing ring on the inner wall of the tank can effectively improve the strength and stiffness of the tank at the raceway, effectively disperse the concentrated load of the tank at the raceway, improve the bearing capacity of the tank, and reduce the weld opening at the connection between the tank and the raceway and the cracking accident of the tank skin at the raceway.