Craft of join of solid state of the new-style hot-rolling that do not have a head

  • Time:
  • Click:73
  • source:JANEZH CNC Machining
Introducing those who do not have head hot-rolling concept is to satisfy the need of the production of all sorts of hot-rolling thin stencil steel and low cost craft. In undertaking do not have head rolling process, needing roll steel in the tail end of the base intermediate of rolling and follow-up the head end of the base intermediate is in the office of a certain position between roughing frame and finish rolling frame to join together, the intermediate base that and repeat is linked together undertakes successive uninterrupted finish rolling. Product line of craft of the rolling that do not have a head needs new setup to heat up a box, join equipment and high speed cut the unit such as machine. The characteristic of craft of the rolling that do not have a head is successive finish rolling, without intermediate cease, rolling rate is constant, did not cut head rolling, give large steel ironworks to will bring the following advantage: 1, enlarge product standards: Can produce more thin stencil steel of Bao Gengkuan, stable rolling is thin and the material of difficult rolling; 2, improve productivity: Reduce time of rolling mill cease considerably, shorten rolling mill is quickened with slowdown time, rolling rate is constant and fixed. 3, improve product quality: Rose to take a ply, protruding to spend the accuracy with width and consistency. 4, raise a product to close so that lead: Make thin and of difficult rolling material owe make friends to fall for lowest, need not undertake cutting a head to board belt, cut trail. 5, economic energy resources: Reduce rolling mill to quicken, the frequency of decelerate. Want to realize the hot-rolling that do not have a head, if engineering technology heats up a box to run technology of technology, successive finish rolling and high speed to cut a technology to wait remain to develop, and among them the most important also be the join technology that the most crucial technology is intermediate base. The difficult problem that development joins the technology is encountered is to should be inside a few seconds what will move is thick and broad intermediate base (~40mm thick, ~2000mm is wide) join is together, and contact intensity wants enough and firm, can endure the concussion of process of follow-up finish rolling. Technology of the hot-rolling that do not have a head is the earliest it is by Japanese JFE1000 Xie Gang the factory was carried out in March 1996, use an induction to solder at that time the join craft that serves as intermediate base. Subsequently minutes of big factory of iron of Japanese new day also used technology of the hot-rolling that do not have a head in April 1998, they use high-power laser beam welding to accept a system. Solder than the fusion that at Japanese iron and steel the enterprise uses technology, riverside make steel and day of 3 water chestnut established development of metallic machinery company to give method of a kind of new-style join, implemented the join technology of innovation. Use this kind of new join technology, small intermediate base can not be in inside 1s time be together by join, it is a kind of the shortest technology when all join craft that at present development comes out are useful. Craft of this kind of join introduces idea of distinctive solid state join, used the act that cuts a head to cut, by local except scale, build receive, joint and cut a head to clear wait for 4 measure composition. The craft of this kind of new development uses stationary join device, and other connection craft uses device of movable type join, shorten greatly thereby product line span. The metallurgy characteristic that technology of this kind of join will introduce below and connect are in the feasibility such as mechanical function to study a result, the key is put in the response of joint intensity, connect to hot-rolling process and field application result. Experimental 　 1.

The carbolic steel that the experiment tries to be produced to commercializing in, medium high-carbon steel and stainless steel had join test, dimensions join equipment tries in, diagnostic parameter sees next tables. The experiment uses material ply 28 ～ 36mm, width limits 200 ～ 450mm, length is unified for 325mm. In experimental process, intermediate base heats 1300 ℃ of 1200 ～ , after heating, place in 60s of the 30 ～ in air, dimensions of imitate hot-rolling rolling mill changes manufacturing condition, subsequently, water of sample classics high pressure is local remove like the scales of a fish, build receive, and joint is together, clear the place that cut a head finally. Because the speed of the biggest join of equipment achieves 150mm/s, the intermediate base inside the ply range that because this is in equipment feature parameter,covers can be in 1s the join that finish. The diagnostic parameter of join equipment expresses 　 -- -- -- -- -- -- -- -- -- , -- 　 of 　 project feature -- , among STS303 and other base ply / width 28~36mm/ is the widest 450mm 　 is local speed of join of water of the high pressure that remove like the scales of a fish / type of join equipment of 　 of 1s of ≤ of the biggest 150mm/s / places time type 　 -- -- -- -- -- , contact cuts the sample with broad 30mm, have corresponding test. To different material, had room temperature or high temperature tensile test respectively. Undertook to medium carbon steel and stainless steel room temperature drawing checks, abecedarian test result displays the resemblance below the joint intensity below room temperature and high temperature. Nevertheless, because high-carbon steel and tall alloy steel were experienced be out of shape Cheng Bei body is mixed martensite hard look, because this checks performance of high temperature drawing. To evaluate the response of pair of rolling processes, contact office data is direct after join hot-rolling, perhaps undertake hot-rolling after heating again. Use frontier department craze to lead (overall length of frontier department crackle is spent / board width) the rolling that index will arrive to measure contact is characteristic, in the meantime, also used actual product line to study the rolling of contact is answered. The contact parallel with two wide 450mm solders together, the around end in sample is brought on solder respectively board, whole sample size is 28mm(T) of × of 840mm(W) × 9000mm(L) . Additional, undertook high temperature curves a test, in process of actual finish rolling with imitate contact is opposite the response that curves force, what studied different steel qualitative connect is macroscopical with microcosmic organization structure. Nextpage 　 　 2.

Company of Xiang Gang iron is in field test riverside riverside factory of the 2nd hot-rolling used technology of the hot-rolling that do not have a head, equipment of the hot-rolling that do not have a head completed installation in July 2006, began not to have the industrialized production of head rolling from January 2007. Use riverside the online monitoring system that oneself develop dogs all the time behavior of frontier department craze. Nevertheless, joint intensity cannot online measure, and the joint intensity that measures after finish rolling does not have important physical sense. The joint intensity after actual measurement finish rolling is almost 100% . Analyse the drawing performance of contact for research, after contact finishs join product line stops, subsequently, be in sampling from contact, have room temperature and high temperature (950 ℃ ) tensile test. Result and discussion 　 1.

Join of joint mechanism solid state is the process that two each fashion an interface by exterior union, from the hot kinetic consideration of craft, freedom of solid state connective can change can express to be type (1) medium - 1.

7 γ , because γ is,be worth, so the process is an initiative reaction. However, this reaction forever won't initiative undertake, because be put in a few bound variable that prevent initiative reaction, the formation that is like the compound between the metal and room like contaminant of skin of rough surface, oxidation, surface and metallurgy effect. Be in all in these bound variable, exterior oxidation skin is the biggest obstacle that makes sure sufficient joint wants to overcome. In be like the technology that the graph shows 2 times, small intermediate base wants classics is local except scale, build receive, finish join through cutting a movement after that, cut in around the appearance that produced not to have oxidation skin on two base intermediate, new formation exterior instantaneous is risen by joint, joint force is the heft of as tangent as the interface shearing force, and new the heat that the attrition between formation two surfaces produces assisted joint process. In fluctuation wedge was designed on two razor blade, control a metal thereby outside side flows, enhance joint power. In joint process, the high pressure of generation builds two receive the air platoon sky between plane, prevented joint face to expose thereby in all round in atmosphere. Cut a movement to be in up and down of two base cause apparently be out of shape greatly, form the new face that does not have oxidation skin, produce attrition heat. In this craft, fluctuation razor blade is put in jackknife, the length of jackknife cries " jackknife is measured " , this is one of the most important craft parameter. Optical metallograph shows the matrix surface of uninfluenced enclothes a thick oxidation skin, and be out of shape the oxidation skin of the area becomes very thin, do not have oxidation skin almost in the contact place of sufficient joint, edge connect handles fine bit of skin of local presence oxidation. Cut a process to bring about the generation on the small area inside jackknife area to be out of shape greatly, jackknife quantity is about 1000% . Although be out of shape hind reservation of exterior oxidation skin comes down, but of area of oxidation skin area and total joint area than, according to crude guess from 100% turn into 10% , 90% new formation area fills minute of ground join to rise, form solid link. γ interface - =-1 of 2 γ free face.

7 γ free face (1) (γ interface ≤ 0.

3 γ free face) in 　 type: γ interface shows contact face can, γ free face shows free face face can. Anyhow, the joint mechanism of new development craft is atomic union, large shearing force makes two apparently atom are stood by, the distance between is in between atom in the action limits of adhesion, accordingly joint instantaneous happens. 2, after the join technology that field test result gives the base intermediate in development and the stability that place of test and verify develops technology, in riverside 2 hot-rolling factory begins to carry out the hot-rolling that do not have a head. Stability of head rolling process is not had after undertaking craft parameter is debugged, riverside the industrialization application that does not have head rolling technology at beginning to undertake in January 2007. Intensity of the connect when using high-pressured water to remove like the scales of a fish is 70% , use local after removing like the scales of a fish, contact intensity exceeds 90% , and the contact intensity of all positions comparatives agree equably. Apply except scale as high-pressured water, rupture mode happening changes, when using high-pressured water to remove like the scales of a fish, rupture happen on base metal. Frontier department craze is led under 5% , and be stabilized as what do not have craft of head hot-rolling join, this value falls gradually. As the progress that the near future works, rate of frontier department craze is controlled at present in under the level of 3% . The application of technology of the rolling that do not have a head also improved product quality, decision board coils the reel-up temperature of mechanical function is quite even, make clear board roll function also agrees equably. Know the ply that coil and width error very small also, and protruding is spent almost same. The experiment proves, the mechanical function error of different position is small reaching constituent uniformity is the immediate result that brings by the rolling that do not have a head. The the most important, basiccest technology in the technology that epilogue joins the technology is to undertake hot-rolling needs to develop do not have a head, iron of riverside Xiang Gang and day of 3 water chestnut establish metallic machinery company to develop a kind to be based on place the craft of new-style solid state join that cuts a concept. The join technology that feasibility researchs to indicate new development satisfied the premise requirement of join process: Joint time short, joint is solid, safeguard easily. On the foundation that studies in the experiment, iron of riverside Xiang Gang in its 2 hot-rolling manufacturer installed line of the hot-rolling that do not have a head, began industrialized production in January 2007. Field test proves joint mechanism work is steady, the effect is apparent, no matter how preform standards varies, joint time is little at 0.

5s, and contact place shows superior mechanical performance. Up to now, the biggest 45 preform (exceed 1000t) be made do not have head hot-rolling continuously, laminose to ultrathin norms (≤ 1.

2t) , successive already rolling goes out the biggest 10 thin plate. Because do not have head rolling mill to produce moving stability, at present 2 hot-rolling factory uses iron of riverside Xiang Gang without head rolling every months of production board coils about 100 thousand T. CNC Milling CNC Machining