Square pipe will show different problems in the manufacturing process, and the problems arising from different manufacturing methods are also different. We will adopt appropriate methods to deal with the problems, so as to ensure the normal use of Square pipe. The following is mainly about the quality defects of Square pipe after heat treatment. Common quality defects of square pipe after heat treatment are: quenching microstructures overheating, underheating, quenching cracks, insufficient hardness, heat treatment deformation, surface decarbonization, soft point, etc.'They have important influence on the service life and accuracy of square pipe. Analyzing the causes of the formation of Juan has an important role in guiding the heat treatment process and prevention.
1. Square tube overheating:
從方管粗糙口上可觀察到淬火后的顯微組織過熱情況。但i 要確切判斷其過熱的程度，必須觀察顯微組織。如果GCrl5鋼的淬火組織中出現粗針狀馬氏體，則為淬火過熱組織。形成原因可是淬火加熱溫度過高或加熱保溫時間太長造成的全面過熱;也可肖巨是因原始組織帶狀碳化物嚴重，在兩帶之間的低碳區形成局部馬氏體針狀粗大，造成的局部過熱。過熱組織中殘留奧氏體增多，尺寸穩定性下降。由于淬火組織過熱，鋼的晶體粗大·會導致方管的核J 性下降·抗沖擊性能降低，方管的壽命也降低。過熱嚴重甚至會造成淬火裂紋。
Overheating of quenched microstructures can be observed from the rough mouth of square tubes. However, in order to determine the degree of overheating, we must observe the microstructures. If coarse acicular martensite appears in the quenched structure of GCrl5 steel, it is quenched superheated structure. The reason is that the quenching heating temperature is too high or the heating holding time is too long, which results in the overall overheating. It can also be said that Xiao Ju is the local overheating caused by the formation of local martensite needle-like coarseness in the low-carbon zone between the two zones due to the serious ribbon carbides in the original structure. The retained austenite in the superheated structure increases and the dimensional stability decreases. Due to the overheating of quenched structure, the coarse crystal of steel will lead to the decrease of core J property, impact resistance and service life of square tube. The severe overheating may even cause quenching cracks. 2、方管熱處理變形：
2. Heat treatment deformation of square pipe:
There are thermal stress and organizational stress in square tube during heat treatment. The internal stress can be superimposed or partially offset each other, which is complex and changeable. Because it can change with the change of heating temperature, heating speed, cooling mode, cooling speed, shape and size of parts, and charging mode, the heat treatment deformation of square tube is unavoidable. Understanding and mastering its changing law can make the deformation of bearing parts (such as the ellipse of alloy tube, size expansion, etc.) in a controllable range, which is conducive to the normal production. Of course, mechanical collision in the heat treatment process will also cause deformation of parts, but this deformation can be reduced and avoided by improving operation.
3. Soft spot of square pipe:
The phenomenon that the local hardness of square tube surface is not enough due to insufficient heating, poor cooling or improper quenching operation is called quenching soft point. Like surface decarbonization, it can cause serious decrease in wear resistance and fatigue strength of the surface, which will cause severe local wear or failure during use.
We will make a deep study of the problems that occur in the heat treatment of square pipes, so that the quality assurance of square pipes can be reasonably utilized. After forming the square tube, we will carry out all-round inspection of the square tube, so that the quality of the square tube can be guaranteed and the customers can be satisfied in practical application. 標簽:
| 廠家分享Q345B方管的耐磨性能體現在哪？ | 保證方管曲折和校直最有效的方法