Sanitary grade stainless steel pipe

Sanitary grade seamless stainless steel pipe production process steelmaking - rolled round steel - perforation - cold drawing - cold rolling - bright annealing - internal surface polishing - external surface polishing - inspection and acceptance - packaging storage. 

The factory production of sanitary grade seamless stainless steel pipe from cold drawing. In the description of several key equipment: 1, cold drawing pipe machine: round steel perforated after called pipe, general pipe is ф 65*5mm or ф 100*7mm. 

General industrial sanitary stainless steel pipe from ф 14*1mm to ф 200*3mm, so the need to expand the tube and pull small tube, cold drawing machine to carry out. Sometimes several tube expansions or tubules are needed, while annealing (heat treatment) and pickling cycles are carried out. The types and specifications of cold drawing tube machine and mandrel types and specifications are not described. The main advantages of cold drawing are: higher production efficiency; It is convenient and flexible to change product specifications during production. 

The equipment and manufacture of the tools and the structure maintenance of the equipment are relatively simple. The main disadvantages of cold drawing are: the deformation of the pass is small, so the processing pass is more, the production cycle is long; Metal consumption is high. Poor finish on the inner and outer surfaces of the tube. 2. Multi-roll cold pipe rolling machine: it is the key equipment to manufacture sanitary seamless stainless steel pipe in China. The outer diameter and wall thickness of the cold-drawn steel tube are less than 0.02-0.05mm after cold rolling.

The inner and outer surface finish of the pipe is Ra≤0.8μm, and the wall thickness can be made up to 0.5mm. After polishing, the inner and outer surface of the tube can reach Ra≤0.2-0.4μm (such as mirror). The types and specifications of multi-roll cold pipe rolling mill and mandrel types and specifications are not described.

 The biggest disadvantage of cold rolled pipe is hard state, that is, the strength of the flexion coefficient is large, it is not suitable for expanding, bending, strictly speaking, or does not meet the national standards, so it is necessary to carry out hot solidification treatment (annealing). In general, the stainless steel tube is treated by the ordinary hot melting furnace (milk furnace), the oxide scale on the inside and outside of the tube needs pickling, which destroys the internal and external surface finish of the original cold rolled tube, and the appearance of small uneven, not up to the sanitary level of pipe surface finish standard. Therefore, the gas protection bright annealing furnace should be selected.

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Sanitary grade seamless stainless steel tube stainless steel is less contains 50% iron and 10.5% chromium, and also add such as nickel, titanium, molybdenum, etc., according to the different components containing the rest, the metal internal microstructure is also different, which has martensite body, ferrite body, austenitic body, double phase, precipitation hardening stainless steel. Sanitary grade seamless stainless steel tubes are also available in different materials. General industry commonly used tube austenitic stainless steel material is more; 0Cr19Ni9 (USU304), 00Cr19Ni11 (USU 304L), 0Cr17Ni12Mo2 (USU 316), 00Cr17Ni14Mo2 (USU 316L), 1Cr18Ni9Ti (SUS 321), etc. To meet the GB/T14976-94 "seamless stainless steel pipe for fluid transmission" standard, as well as the internal and external surface finish requirements of the steel pipe. Choose sanitary grade seamless stainless steel tubes with the type of fluid medium, concentration, temperature, pressure, flow speed, and other factors.


Post time: Sep-16-2021