?? Shandong shunxinda Machinery Co., Ltd. (13969559358) is located in Liaocheng Economic Development Zone, Jiangbei water city with beautiful scenery. It is a company specializing in the production, processing and sales of precision seamless pipe, cold drawn precision seamless pipe and cold-rolled precision seamless pipe
????????? Improvement of straightening and cracking of 20Cr precision steel tube by industrial heating extrusion
??????? For a long time, the cause analysis and control of 20 CR precision steel tube extrusion pipe straightening cracking ? Extruded pipe is a mature product produced by Jiangyou Changcheng Special Steel Co., Ltd. of Panzhihua Iron and steel group. The quality of the product is relatively stable from the aspects of steelmaking, rolling, extrusion, solid solution and straightening. In the early stage, 3 heats of steel pipe were produced continuously, and smelting, blooming and extrusion were normal. When the finished pipe was straightened, a large proportion of spiral cracks appeared on the 413v1-2691 steel pipe. After temperature straightening at about 150 ¡æ, there was no such crack in the spot straightening process of the precision Q345B precision bright tube. However, due to the incomplete plastic deformation of the warm straightening system, there was a small amount of elastic deformation. After cooling, the straightening part of the steel pipe was bent again, so the straightening work of the furnace steel pipe could not continue. In this paper, the causes of the spiral cracks in straightening of the furnace are discussed. Measures are taken to effectively control the cracks and improve the process. During the same period, three heats of tp446-1 extruded tubes were produced continuously, and one of them cracked during straightening. Production process route: electric furnace smelting + 825mm rolling mill blooming + 3150mm extruder extrusion water cooling. The straightening and cracking furnace number is 413v1-269. The specifications of the finished pipe are 89mm4mm and 76mm8mm. The chemical composition and other testing items meet the requirements of corresponding technical standards. 1.1 the shape of spiral crack during straightening is shown in Figure 1. It can be seen that the crack extends from the clamping end of straightener to the middle.
???? Analysis of the factors affecting the vacuum heat treatment quality of titanium and 20Cr precision steel tubes at present, pure titanium and 20Cr precision steel tubes are mainly prepared by cold rolling. The microstructure and properties of the cold processed pipes have changed greatly. The strength and hardness increase, the plasticity and toughness decrease, which makes the subsequent processing difficult. Therefore, vacuum annealing is required for each pass of rolling to eliminate work hardening, The microstructure and properties are restored to the state before processing, and then rolling is continued until the finished pipe is prepared. Due to the high chemical activity of titanium, when the temperature is higher than 550 ¡æ ~ 600 ¡æ, hydrogen, oxygen, nitrogen, carbon and other interstitial elements are easy to penetrate into the metal surface. Below 1000 ¡æ, oxygen penetration is the main reason. The pollution layer consists of oxide and gas saturated layer, with high hardness and low plasticity Blue and black phenomenon, as shown in Figure 1; On the other hand, after vacuum annealing of the same batch of pipes, the strength of some tubes is higher and the microstructure does not recrystallize completely. In view of the problems encountered in the actual production process, this paper analyzes the vacuum degree of heat treatment furnace, the quality of oleic acid washing, the cleanliness of annealing furnace and the way of annealing furnace charging, so as to guide the control points of titanium pipe annealing process and promote the improvement of tube annealing quality.
?? The company reserves a variety of specifications of precision seamless pipe, cold drawn precision seamless pipe, cold-rolled precision seamless pipe, perennial business in Tianjin, Baotou Steel, Baosteel, Hengyang, Angang, Chengdu, Yegang, Lubao, Anyang, Jiangyin, Hongdu and other high-quality seamless steel pipe, alloy steel pipe, high-pressure boiler pipe, alloy high-pressure seamless pipe, thick wall seamless pipe, fluid pipe, structural pipe, chemical fertilizer special pipe, Petroleum cracking pipe, low pressure boiler pipe, large diameter seamless pipe, large diameter welded pipe, precision steel pipe, etc. The materials of common resources are: 10 ¡Á 10, 20 ¡Á 10, 45 ¡Á 10, 16Mn, 27SiMn, 12Cr1MoV, 15CrMo, 12Cr1MoVG, 15CrMoG, 10CrMo910, 20Cr, 40Cr, 35CrMo, 304, 316, 316L, 310S, 309S, etc.