The basic process flow of stainless steel pipe fittings mainly includes blanking, forming, welding, heat treatment, surface treatment, cutting, nondestructive testing, surface protection and marking.
The stainless steel pipe fitting is usually made of stainless steel pipe, stainless steel plate and stainless steel bar, the blanking method is determined by the material properties and the shape of the product.
For different shapes, sizes and processing requirements of the blank have different processing regulations.
Cutting method for band sawing machine sawing machine or bow cutting, gas cutting, plasma cutting and other commonly used stainless steel pipe.
The material method of stainless steel sheet under common cutting, plasma cutting, punching and cutting.
The material method commonly used stainless steel bars under the band saw cutting, punching and cutting or sawing bow.
The forming process is a necessary step for any stainless steel pipe. The final product is different, the forming process is not the same, the following brief introduction to the forming process of heating and welding.
If the stainless steel pipe fitting is made of hot forming method, to meet the requirements of deformation in the forming process. The heating temperature is determined by the material and process requirements.
Hot bend or hot bending forming, heating method is generally less induction or high frequency part is heated by the flame. This heating method is a continuous heating with the elbow or bend forming process, the pipe is heated in the movement and the forming process is completed.
Hot pressing elbow, hot pressing three pass or forging forming, the heating method is usually used in the furnace, flame heating, induction heating or electric heating, etc.. In this way, the pipe blank is heated to the required temperature, and then pressed into the mould to be pressed or forged.
There are two kinds of welded stainless steel pipe fittings, one is made of welded pipe fittings, the fittings factory, forming process of seamless pipe and welded pipe forming process, forming process of stainless steel pipe fitting is no welding process; the other is a stainless steel pipe fitting forming the factory to complete required welding process by fittings, such as elbows, pressing after monolithic assembly welding with rolling steel plate after welding a pipe and then pressed three etc..
Commonly used welding methods of stainless steel pipe fittings are manual arc welding, gas shielded welding and automatic welding.
The heat treatment process is an important part of the stainless steel pipe fitting manufacturing process. After heating, insulation and cooling of the heat treatment process, you can eliminate the pipe in the forming process of work hardening, residual stress, metal deformation defects, etc., can improve or even improve the metal structure and performance after forming.
Stainless steel pipe fitting's surface treatment methods are generally sandblasting, shot blasting, grinding, pickling, etc., used to remove the surface corrosion, scratches, etc., to keep the surface smooth, so as to meet the processing and inspection requirements.
Cutting is to complete the stainless steel pipe fitting welding end, structural size, shape and position tolerance processing process. Sometimes the cutting process also includes the inner and outer diameter of the tube. This process is usually done by means of a dedicated machine or general purpose machine. If the size of the pipe fitting is too large and the existing machine is not capable of machining it, it can be processed in other ways, such as the method of grinding after gas cutting. Generally in the cutting after the appearance of stainless steel pipe fitting and size inspection.
Nondestructive testing is an important process for inspecting defects that may occur in the machining of materials and pipe fittings. In addition to meet the requirements of product standards and ordering requirements for non-destructive testing, some of the more stringent quality control of the factory also based on materials, processing technology and internal quality control requirements to develop non-destructive testing requirements to ensure that the quality of manufactured products.
In practice, the determination of the grade of non-destructive testing of pipe fittings shall be determined in accordance with the requirements of the order or the standard. If the surface of the pipe is basically the original pipe, plate or forging state, the non-destructive testing of the surface quality of the pipe (MT, PT), if no clear grade requirements can be according to Ⅱ level, but regardless of how qualified, The depth of the crack is not easy to determine the depth of the defect should be regarded as unqualified. In the case of non-destructive testing of the internal quality of the pipe (RT, UT,), if there is no clear grade, the ray detection shall be in accordance with Class II (eg weld inspection).
In order to prevent defects in the product during the heat treatment, the final non-destructive testing of the pipe shall be carried out after the heat treatment.
Domestic pipe manufacturer NDT is usually used JB / T 4730 specification. Personnel engaged in non-destructive testing shall obtain the corresponding qualifications in accordance with the relevant provisions.
Generally, the surface of the stainless steel pipe fitting is protected by the first passivation method. If the entire surface of the stainless steel pipe is machined, no passivation treatment is required. The main purpose of the surface protection of stainless steel fittings is corrosion, but also the appearance of the appearance of the pipe. Of course, the manufacturer will be based on the requirements of the order of some beautiful appearance.
The logo is an integral part of stainless steel pipe fittings and is the basis for achieving traceability requirements. Often, the content and method of the mark are specified in the product standard. The markings of the pipe fittings generally include the manufacturer's name or name, material grade, specifications, and other requirements for the order. Marking methods include permanent signs such as stamping, engraving, electro-erosion, etc ...
Of course, in addition to the above conventional process manufacturing process, there are some other processes. For example, in order to control the quality of raw materials, the manufacturer should also carry out the inspection of raw and auxiliary materials to ensure the accuracy of materials used; to meet the special requirements of materials or customers, to the metal metallographic organization, intergranular corrosion test to ensure the final Finished products can fully meet customer needs.
Source: Yaang Pipe Industry Co., Limited (www.yaang.com)