Development of Stainless Steel Pipes for Oil and Gas in China(4)

5.3 manufacturing method of stainless-steel Oil and gasoline properly Pipes of numerous sorts(1) 13Cr collection 316 chrome steel sheet Forging, rolling (stripping, punching the hole) - heating - perforation - continuous rolling - sizing - cooling - reducing - heat remedyQuenching - tempering - warmth sizing - hot straightening - shot peening - flaw detection - water strain - threading - inspection - packaging(2) Duplex stainless-steelForging, rolling (stripping, punching) - heating - piercing - non-stop rolling - sizing - cooling - reducing - warmth treatmentanswer treatment - heat sizing - hot straightening - shot peening - flaw detection - water stress - thread processing - inspection - packaging(3) Nickel-primarily based alloysForging billet (skinning, drilling thru the hole) - heating - lubrication, reaming - heating - lubrication, extrusion - solution treatment - bloodless rolling - flaw detection - water strain - thread processing - Inspection - Packagingfive.4 technique difficulties(1) Ring furnace heating approach and interest factorsAt gift, the corporations that produce oil properly pipes and chrome steel in China are all adopting the annular heating furnace. Ring furnace is suitable for the manufacturing of seamless metallic pipes, used for heating 304L Stainless Steel Bar, smooth to oxidize the billet and cause choppy heating, and so forth. consequently, the subsequent factors have to be noted inside the heating technique: below the basis of making sure whole combustion of natural gas, the heating phase need to be decrease the air extra coefficient to make certain that the furnace is in a weak oxidizing environment. The excess wide variety of air within the soaking phase ought to be slightly better to ensure that the generated iron oxide pores and skin may be removed; the heating temperature of the tube clean within the heating region and the soaking sector is absolute. can't exceed the control range of the target temperature, otherwise it's going to growth its ferrite, affecting the thermal processing overall performance and the arrival of floor defects; chrome steel tube because of low thermal conductivity, massive expansion coefficient, requiring six hundred to 800 stages to strictly manipulate the heating speed, heating cannot be too speedy, otherwise it's miles vulnerable to cracking; whilst the stainless steel tube is hooked up in the furnace, the rhythm of different carbon metal within the furnace should be to make certain that every phase of the 316L Stainless Steel Bar inside the furnace time principle, to make sure the stainless-steel tube inside the important heating time for each segment; make certain the smooth operation of the production, prevent the tube blank from being heated inside the furnace for a long time, and motive heating problems inclusive of overheating and overheating;(2) Optimize steel deformation conditions at some point of perforationFrom the perspective of the development technique of the two-roller punching device, the evolution from the barrel roll to the conical roll puncher has ended in steel flow speeds ranging from "small-big-small" to massive torsional deformations within the steel at some point of perforation. In an irrational nation, the metallic drift rate step by step increases (the metal torsion significantly decreases) in an affordable nation. these adjustments are conducive to low plasticity stainless-steel tube piercing, decreasing the occurrence of defects.comparing the performance index of the piercing system is not most effective an development of the elongation rate, but additionally the capability of the piercing mill to penetrate the alloy metal. inside the case of two-roll perforation, alternating tensile and compressive stresses act in the location of??the important line of the tube blank (from the point of indentation to the cease of the pinnacle) and the tensile strain is in a plane perpendicular to the road of action of the roll. the quantity of pressure before the pinnacle is confined with the aid of the amount of important pressure (in general, the amount of discount earlier than the pinnacle adjustments within the variety of 4% to 9%). whilst the important stress is passed, the middle of the tube collapses. The middle of the tube has internal cracks or cavities, leading to defects along with cracks, folds, and spalls within the capillary tube. In phrases of process parameters, the primary points of the cone-roller punching device are angle values, particularly the roll-rolling perspective and the feed-in angle. the previous is a fixed price for a unit, and the latter is an adjustable feed angle. The diverse combos of roll and feed angles can have a good sized impact at the shear deformation during the piercing system.

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