CN-116984407-B - Cold drawing process of austenitic stainless asymmetric wall thickness steel pipe

CN116984407BCN 116984407 BCN116984407 BCN 116984407BCN-116984407-B

Abstract

The invention discloses a cold drawing process of an austenitic stainless asymmetric wall thickness steel pipe, which comprises the steps of selecting an asymmetric cold drawing outer die with an inlet hole taper; the second step is to select a cold-drawing inner mold with conical shape, the third step is to assemble the cold-drawing outer mold, the cold-drawing inner mold and the hydraulic drawing machine, and the fourth step is to send the austenitic stainless steel pipe into the hydraulic drawing machine to cooperate with the cold-drawing outer mold and the cold-drawing inner mold to perform three-pass cold drawing. Compared with the traditional machining, the invention greatly shortens the production period of the asymmetric wall thickness steel pipe, improves the production efficiency, effectively controls the external dimension and the wall thickness precision of the product by the mutual matching of the inner die and the outer die, and has bright and smooth surface quality.

Inventors

PENG HAILONG
LV JIANGANG
YANG MINGAN
JIANG CHAOFEI
Chen Shuangsen
YANG YULING

Assignees

众山(常州)新材料有限公司

Dates

Publication Date: 20260505
Application Date: 20230829

Claims (4)

1. A cold drawing process of an austenitic stainless asymmetric wall thickness steel pipe is characterized by comprising the following steps of: step one, selecting a cold-drawing outer die which is asymmetric and has inlet hole taper; step two, selecting a cold-drawing internal mold with a conical shape and a taper; step three, assembling the cold-drawn outer die, the cold-drawn inner die and hydraulic drawing equipment; Sending the austenitic stainless steel tube into a hydraulic drawing machine to be matched with a cold drawing outer die and a cold drawing inner die for three-pass cold drawing; The cold drawing deformation rate is reasonably distributed in each pass, a pressing device is additionally arranged outside the outlet end of the cold drawing outer die and used for keeping the center line of the steel pipe consistent with the drawing center line, the matching is suitable for drawing speed and deformation rate, and cold drawing lubricant is required to be added in the cold drawing process; The cold-drawing outer die is internally provided with asymmetric holes, and each hole comprises an outlet hole section (1), a sizing hole section (2) and an inlet hole section (3), wherein the taper angles of two opposite faces of the inlet hole section (3) are alpha and beta respectively and have values of 6-9 degrees; the cold-drawing internal mold comprises a sizing section, a reverse taper section, a chamfer section and a thread section which are integrally formed, wherein the taper angle of the reverse taper section of the cold-drawing internal mold is 7-10 degrees.
2. The cold drawing process of the austenitic stainless asymmetric wall thickness steel pipe according to claim 1, wherein the cold drawing process is characterized by further comprising the step of carrying out inner and outer surface solution treatment on the austenitic stainless steel pipe between three cold drawing processes, wherein the solution temperature is 1040-1100 ℃.
3. The cold drawing process of the austenitic stainless asymmetric wall thickness steel pipe according to claim 2, wherein the austenitic stainless asymmetric wall thickness steel pipe is cooled to below 200 ℃ by adopting a very fast cooling mode after each solid solution treatment, the cooling medium is circulating cooling water, and the cooling speed is controlled to be 100-300 ℃ per minute.
4. The cold drawing process of an austenitic stainless asymmetric wall thickness steel pipe according to claim 1, wherein in the fourth step, the deformation rate of cold drawing performed three passes is controlled to be 25.54% in the first pass, 8.25% in the second pass, and 5.59% in the third pass.

Description

Cold drawing process of austenitic stainless asymmetric wall thickness steel pipe Technical Field The invention relates to the technical field of steel tube machining, in particular to a cold drawing process of an austenitic stainless asymmetric wall thickness steel tube. Background Some parts in the electronic industry are made of stainless steel (such as austenitic stainless steel), the product is regular in appearance, special in inner hole and unequal in wall on each side, the requirements on dimensional accuracy, surface quality and hardness (the outer part is 210-330 HV1, the inner part is 175-265 HV1) are high, a machining mode is mainly adopted at present, the machining period is long, raw material consumption is high, cost is high, production efficiency is low in mass production, and the product yield is low (25-35%). In order to overcome the defects existing in the existing machining mode, the compression machining period is shortened, raw material consumption is reduced, production efficiency is improved, production cost is reduced, product yield is improved, and a cold drawing process of the austenitic stainless asymmetric wall thickness steel pipe is required to be designed for cold machining of the product. Disclosure of Invention This section is intended to outline some aspects of embodiments of the application and to briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section as well as in the description of the application and in the title of the application, which may not be used to limit the scope of the application. The present invention has been made in view of the above-mentioned problems occurring in the prior art. Therefore, the invention aims to provide a cold drawing process of an austenitic stainless asymmetric wall thickness steel pipe, which aims to solve the problems of long processing period, high raw material consumption, high cost and low production efficiency in mass production of the asymmetric wall thickness steel pipe. In order to solve the technical problems, the invention provides the following technical scheme that the cold drawing process of the austenitic stainless asymmetric wall thickness steel pipe comprises the following steps: step one, selecting a cold-drawing outer die which is asymmetric and has inlet hole taper; step two, selecting a cold-drawing internal mold with a conical shape and a taper; step three, assembling the cold-drawn outer die, the cold-drawn inner die and hydraulic drawing equipment; Sending the austenitic stainless steel tube into a hydraulic drawing machine to be matched with a cold drawing outer die and a cold drawing inner die for three-pass cold drawing; The cold drawing deformation rate is reasonably distributed in each pass, a pressing device is additionally arranged outside the outlet end of the cold drawing outer die and used for keeping the center line of the steel pipe consistent with the drawing center line, the matching is suitable for drawing speed and deformation rate, and cold drawing lubricant is required to be added in the cold drawing process. As a preferable scheme of the cold drawing process of the austenitic stainless asymmetric wall thickness steel pipe, the cold drawing outer die is internally provided with asymmetric holes, each cold drawing outer die comprises an outlet hole section, a sizing Kong Duanyi and an inlet hole section, the taper angles of two opposite surfaces of the inlet hole section are respectively alpha and beta, and the taper angles are 6-9 degrees. As a preferable scheme of the cold drawing process of the austenitic stainless asymmetric wall thickness steel pipe, the cold drawing internal mold comprises a sizing section, a reverse taper section, a chamfer section and a thread section which are integrally formed, wherein the taper angle of the reverse taper section of the cold drawing internal mold is 7-10 degrees. As a preferable scheme of the cold drawing process of the austenitic stainless asymmetric wall thickness steel pipe, the cold drawing process further comprises the step of carrying out internal and external surface solid solution treatment on the austenitic stainless steel pipe between three times of cold drawing, wherein the solid solution temperature is 1040-1100 ℃. The cold drawing process of the austenitic stainless asymmetric wall thickness steel pipe is characterized in that the austenitic stainless asymmetric wall thickness steel pipe is cooled to below 200 ℃ in a very fast cooling mode after solution treatment, cooling medium is circulating cooling water, and the cooling speed is controlled to be 100-300 ℃ per minute. As a preferable scheme of the cold drawing process of the austenitic stainless asymmetric wall thickness steel pipe, in the fourth step, the deformation rate of cold drawing for three passes is controlled to be 25.54% for the first pass, 8.25% for the second pass and 5.59% for the third pass. Compared with the tradition