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Work Technology of Stainless Steel Seamless pipe
2018-04-03
The price of stainless steel seamless tube is high, because there are three reasons:much processing and testing links,excellent equipment requirements,and the skilled workers.
preliminary work
Whenever purchase a batch of stainless steel billet( round bar),we do strictly examine the quantity and quality,and then write the corresponding test and test report.When the customers order the stainless steel seamless pipes,we have to do a series of things as follow according to the requirements:the technical department gives the process diagram or product diagram，and then the production management department organizes the production.
After the production,we need to examine them again.according to the conclusion the the examine,The stainless steel ingots are polished to remove burrs, scratches and small pits till the size and surface can meet the requirements.Then, according to the specifications of the product, the stainless steel ingot should be sent to the corresponding processing place, waiting for the processing of the subsequent parts.
Seamless steel tube forming
When the stainless steel ingot arrives at the mill, the next step is to take shape according to the size of the drawing.The specific operation procedure is roughly: the first step is to heat the extrusion first, and then the hot extrusion is done to remove the surface oxidation layer.The second step is to cold stretching (stretching frequency can be a, also can be several times, depending on the wall thickness of the seamless the case may be), then the pickling, followed by heat treatment, in order to eliminate tensile material produced by after hardening.The requirement here is that whenever you stretch, you must have a corresponding pickling and heat treatment.Again here is for cold rolling (cold rolled it may be a time, also can be several times, depending on the technological requirements and decide), each time the same for cold rolling, all have to conduct a pickling and heat treatment, reason is to remove the oxide layer on the surface of the material, eliminate the material of produced by cold rolling after hardening.
Precision up to standard
According to the above the cold drawing and cold rolling processing of stainless steel seamless tube, is only as a semi-finished products, precision level is very low, often could not reach the requirements of users, such as uneven wall thickness and knocked wounded, both inside and outside surface marks or spots or pit defects, such as for grinding.The specific operation procedure is: first, the cold drawn and cold rolled stainless steel seamless tube, carry on the detection, according to the detection situation, to the defect site to carry on the grinding.Grinding form, for small diameter thin - wall seamless tube, usually used is the mechanical integral grinding.For the medium and large diameter thick wall seamless pipe, if the whole defect problem, the use of mechanical grinding;If it is a defect problem in a local area, manual repair is used(this is much common).
The length of stainless steel seamless pipe is generally controlled between 6~8 m. If the user is more casual about the length, the length of a batch of stainless steel tubes need not be strict.If a specific request is made, it is required to cut and equal length.
Test
In addition to the inspection work, it is necessary for the grinder to inspect the finished product from time to time. After the finished product is finished, it needs to be checked by a full-time inspector, and the random inspector will conduct the random inspection.If the problem is found during the review, it is determined whether the problem is re-examined.
The main tools for testing are measuring instruments (calipers, micrometers, measuring tape, etc.) and thickness gauges, which are normal objects.Because the detection link is much, layer by layer gateways, so generally not easy to appear careless.After confirm that meet the design requirements, then the pressure test, pressure test is usually do first, and then do the hydrostatic test (test pressure value according to the user request), through after, again according to user requirements, do or not do inspection.(using direct reading spectrometer, eddy current test, ultrasonic flaw detection, etc.) and polishing, the last link is pickling.After that, the seal is affixed on each stainless steel tube. After the packaging is finished, the label is hung, and the container is packed or not boxed.
