Stainless steel seamless pipe processing technology
Several steps of stainless steel seamless pipe processing technology:
First, according to the customer's requirements, the stainless steel round bar is cut into specified lengths, and then peeled on a lathe. After completion, the holes are drilled on a horizontal drilling machine. One end of the hole is tapered and formed into a V shape, and the rest is It is a small straight cylindrical hole. After machining is completed, it must be inspected. According to the inspection results, the stainless steel ingot must be ground to remove burrs, pull marks, small pits, etc. until it reaches the specified size and surface requirements. Then, according to the product specifications, the stainless steel ingots are sent to the corresponding processing locations at a price, such as the subordinate steel rolling factory, to wait for subsequent parts of the processing.
After the stainless steel ingots arrive at the steel rolling branch, the next step is to shape them according to the drawing and size requirements. The specific operating procedures are roughly as follows: the first step is to perform heating and extrusion. After hot extrusion is completed, pickling is performed to remove the surface oxide layer. The second step is to carry out cold stretching (the number of stretching can be one time or several times, depending on the wall thickness of the seamless pipe), followed by pickling, followed by heat treatment to eliminate the effects of stretching. The resulting material hardens; the requirement here is that every time it is stretched, it must undergo a corresponding pickling and heat treatment. The next step is to carry out cold rolling (cold rolling can be once or several times, depending on the process requirements). Similarly, every time hot rolling is performed, pickling and heat treatment must be carried out. The reason is to remove The oxide layer on the material surface eliminates the material hardening caused by cold rolling.
It is worth mentioning that the number of cold drawing and cold rolling does not necessarily correspond one to one. It can be several times more cold drawing, or it can be more times cold rolling, or it can even be only cold drawing without cold rolling, or only cold rolling without cold drawing. The process will be formulated according to the specific situation of the product and operated according to the process requirements. Furthermore, the commonality between cold drawing and cold rolling by manufacturers is that they can make the wall thickness of semi-finished stainless steel seamless pipes thinner and the length increase. The difference is that the former operation is faster, but the one-time increase is relatively small; while the latter operation is more time-consuming, but the one-time increase can be larger. The company's cold drawing and cold rolling are all carried out on automated equipment. The operators only need to install the workpieces and operate the control buttons after debugging, so the work efficiency is relatively high. The heat treatment is also automated. The workpiece enters from one end of the furnace and comes out from the other end and runs continuously. The time depends on the user's requirements for the product, wall thickness, size and material conditions. It can be as fast as less than 4 to 5 minutes. Some are slower than 7~8 minutes.
The stainless steel seamless pipes processed according to the above-mentioned cold drawing and cold rolling can only be regarded as semi-finished products, and the accuracy level is very low. They often fail to meet the requirements put forward by users, such as uneven pipe wall thickness and bumps. If defects such as scratches, scratches, spots or pits on the inner and outer surfaces are found, they must be repaired. The specific operating procedure is: first, inspect the cold-drawn and cold-rolled stainless steel seamless pipes, and then grind the defective parts according to the inspection results. In the form of grinding, for small-diameter thin-walled seamless pipes, mechanical integral grinding is usually used. For thick-walled seamless pipes of medium and large diameters, if the problem is an overall defect, mechanical grinding is used; if it is a local defect, manual grinding is used (this situation is relatively common), and manual tools are used. For portable electric sanders and upside-down sanders.
