Online water cooling is different from the off-line solid solution, online water cooling without again on the steel pipe heating, how to use the deformation of waste heat for on-line processing to ensure that the mechanical properties of steel pipe to meet the follow-up processing requirements.In the production of austenitic stainless 718 steel Company steel seamless pipe, the following technical difficulties:(1) To determine the stainless steel pipe blank heating process to develop a certain degree of difficulty.Stainless steel has excellent corrosion resistance, formability and a wide range of strength and toughness in a wide range of characteristics, in heavy industry, light industry, daily necessities industry and building decoration and other industries are widely used. The use of online water heat treatment, stainless steel seamless steel pipe into the water temperature control in the 920 ~ 950 , which can effectively ensure that all aspects of performance to meet the requirements of the subsequent cold processing, to achieve the purpose of replacing the field of solid solution..(2) Deformation process parameters set to be re-selected, significantly different from the carbon steel pipe.
Especially in the boiler industry as an important base for heat exchangers to use. Due to the limited amount of deformation per pass, to produce finished products often need more than the cold or cold drawn. At high temperatures, too long high temperature holding time and high insulation temperature easily lead to blank grain grain structure to produce δ ferrite and the phenomenon of grain growth serious phenomenon, resulting in defects in the steel pipe surface.(3) Stainless steel pipe online water heat treatment technology needs to be established.
Due to the cold working hardening and surface quality of stainless steel, a series of treatments such as annealing heat treatment, pickling and lubrication are required before each cold rolling or cold drawing. Compared with the carbon steel pipe, the stainless steel pipe has the characteristics of large deformation resistance, large thermal expansion coefficient, low thermal conductivity in the low temperature range, wide width and easy to stick, and the setting of the process parameters Carbon steel pipe is significantly different. In the heating system design, in order to ensure the quality of heating, heating speed must be controlled within a reasonable range.
Stainless steel heating temperature range is narrow, the thermal conductivity and carbon steel is also a big difference. 300 series of austenitic stainless steel smls pipe because of its good overall performance in the boiler, petrochemical industry has been widely used.Design and development of “hot rolling (perforation + sizing) + on-line water cooling” Φ89mm production of stainless steel seamless steel pipe blank production process, can reduce the middle of cold rolling (pull) pass, greatly simplifying the process. The complicated process brings long problems such as long production process, long production cycle, low output, low yield, high cost and pickling pollution environment. Since the 300 series of stainless steel seamless pipe since the emergence of a large number of production and processing enterprises, the main production process routes are: “perforation + multi-pass cold-rolled (pull)” or “squeeze + multi-pass cold ) “
Tags: 718 steel Company
DEWD