Steel of carbolic steel, low alloy excel in of pressure vessel solder

0 ％ . In addition, the quantity that contain manganese does not exceed 1.

2 ％ , the quantity that contain silicon does not exceed 0.

5 ％ , neither of Si, Mn serves as alloying element. And other element, wait like Ni, Cr, Cu, control is inside incomplete surplus limit, not be alloying element more. S, P, O, N regard foreign matter as the element, according to rolled steel breed and grade, also have strict restriction. What carbolic steel measures according to containing carbon is different, cent is mild steel (C ≤ 0.

30 ％ ) , medium carbon steel (C= 0.

30 ％ ~ 0.

60 ％ ) , high-carbon steel (C ≥ 0.

60 ％ ) . Main pressure part uses pressure vessel carbolic steel, mild steel of main be confined to. Be in " look compasses " in regulation: "Use at soldering structural pressure vessel is main the carbon steel of pressure part and low-alloy steel, its contain carbolic quantity to should not be more than 0.

25 ％ . Below special condition, if choose,contain carbolic quantity to exceed 0.

The rolled steel of 25 ％ , should demarcate carbon equivalent is more than 0.

45 ％ , ask for so that the user agrees by production unit, approve via making total controller of technology of unit pressure vessel, deal with approval procedures by relevant provision " . Commonly used pressure vessel has Q235-B, Q235-C with carbolic steel brand, 10, 20, 20R. (one) mild steel solders characteristic mild steel contains carbon the amount is small, content of manganese, silicon is little, connecting general reason condition to fall to won't cause serious organization sclerosis because of soldering or appear quench organization. The plasticity of this kind of steel and concussion tenacity are admirable, its solder the plasticity of contact, tenacity is extremely good also. Warm-up and postheat do not need commonly when soldering, do not need to take special craft step, can obtain quality to solder approvingly contact, steel has reason mild steel to solder admirably function, it is can best steel plants the weldability in all rolled steel. (2) mild steel solders point (1) solder wiring energy is like when the solder that bury arc too big, the grain that can make heat affects area of area thick any crystalline substance is too bulky, can produce organization of family name of the Kingdom of Wei even, make the concussion tenacity of this area is mixed thereby curve function to reduce, cause impact tenacity and curve function unqualified. Reason is using the solder that bury arc to solder, solder especially thick board when, should press strictly via soldering the solder wiring energy of craft assess qualification applies solder. (2) solder below condition of spot low temperature, solder when the welding line with ply or bigger tigidity, because solder contact cooling rate is rapidder, the tendency of cold crack increases. Solder to avoid crackle, should take the step such as the warm-up before solder. 2, pressure vessel reachs his to solder with steel of low alloy excel in the characteristic is in a kind a few affiliation in steel outside de-carbon or a variety of alloying element (alloying element gross is under 5 ％ ) , in order to improve the mechanical performance of steel, make its succumb intensity is in 275 MPa above, have good integral performance, this kind of steel says for steel of low alloy excel in, its are main the characteristic is intensity tall, plasticity and tenacity are better also. Those who press steel succumb intensity level and heat treatment condition, pressure vessel can be divided with steel of low alloy excel in it is 2 kinds. Steel of ① hot-rolling, normalizing succumbs intensity is between 294Mpa ~ 490MPa, its are used condition is hot-rolling, normalizing or accuse make friends state, belong to steel of aggrandizement of blame heat treatment, this kind of steel application is most wide. Attune of ② low carbon pledges steel succumbs intensity is between 490Mpa ~ 980Mpa, pledge be used below condition in tone, belong to steel of heat treatment aggrandizement. Its characteristic is to have high strength already, and plasticity and tenacity are better also, can pledge solder below condition in tone directly. In recent years, application of qualitative steel of attune of this kind of low carbon is increasingly wide. Apply at the steel of low alloy excel in of pressure vessel at present. Armor plate brand has: 16MnR, 15MnVR, 13MnNiMoNbR, 18MnMoNbR. Forging brand has 16Mn, 15MnV, 20MnMo, 20MnMoNb to wait. The quantity containing carbon of steel of low alloy excel in does not exceed 0 commonly.

20 ％ , alloying element gross does not exceed 5 ％ commonly. Because steel of low alloy excel in contains the alloying element of certain amount, make its weldability can have certain difference with carbolic steel, its solder characteristic expression is in: (one) solder of contact solder crackle (1) because steel of excel in of cold crack low alloy is contained make the element such as the C of rolled steel aggrandizement, Mn, V, Nb, easy when solder temper by dipping in water is hard, these sclerotic organizations are very sensitive, accordingly, in rigid bigger or cabined stress high case falls, if solder craft is undeserved, produce cold crack very easily. And this kind of crackle has certain defer sex, its harm is great. (2) reheat (SR) crackle reheat crackle is to solder to contact eliminates process of stress heat treatment after solder or be in high temperature for a long time to run medium in the edge brilliant craze that nears area of weld junction thick any crystalline substance happening. Think commonly, because solder,its arise is high temperature makes the carbide such as the V near HAZ, Nb, Cr, Mo originallies dissolve in austenite, when cooling after solder, have not enough time separate out, and dispersion separate out is shown when PWHT, thereby aggrandizement inside brilliant, the creep when making stress flabby is out of shape center at crystal boundary. Steel of low alloy excel in solders contact produces reheat crackle not easily commonly, wait like 16MnR, 15MnVR. But steel of excel in of low to Mn-Mo-Nb and Mn-Mo-V department alloy, be like 07MnCrMoVR, because Nb, V, Mo is to make the element with reheat crackle stronger sensitivity, because this kind of steel is in after solder when heat treatment,should notice the sensitive temperature area of escape reheat crackle, prevent the happening of reheat crackle. (2) solder of contact fragile change and bate (1) strain ageing is fragile change solder contact needs to endure all sorts of cold working before solder (next makings are cut, cylindrical shell coils the) such as the circle, rolled steel can produce plasticity to be out of shape, if this area is met via the hot action of ℃ of 200 ~ 450 again,cause strain ageing. Strain ageing is fragile change can make rolled steel plasticity is reduced, brittleness transition temperature rises, bring about equipment thereby fragile break. PWHT can be eliminated solder structure this kind of strain ageing, make tenacity restores. GB150-1998 " steeliness pressure vessel " make a provision, s of δ of ply of cylinder rolled steel accords with the following condition: The ply of carbon steel, 16MnR is not less than the 3 ％ of Di of cylinder internal diameter; 2 what the ply of other low-alloy steel is not less than Di of cylinder internal diameter.

5 ％ . And be cold figuration or in the pressure part of lukewarm figuration, answer to have heat treatment after figuration. (2) welding line and hot influence area are fragile change soldering is inhomogenous heat and cooling process, form inhomogenous organization thereby. Welding line (WM) and hot influence area (the brittleness transition temperature of HAZ) is higher than mother capable person, it is the weak point in contact. Solder wiring energy has main effect to WM of steel of low alloy excel in and HAZ function, easy temper by dipping in water of steel of low alloy excel in is hard, line capabilities is too small, HAZ can appear martensite causes crackle; Line capabilities is too big, the grain crude mass rally of WM and HAZ causes contact fragile change. Low carbon attune pledges photograph of steel of steel and hot-rolling, normalizing is compared, too big to line capabilities and the HAZ that cause is fragile change the trend more serious. When soldering so, should be in line capabilities limitation certain limits. (3) solder because the bate of hot influence area of contact solders hot action, the hot influence area that low carbon moves qualitative steel (the side outside HAZ) heats temper temperature above especially the area near Ac1, the bate that can produce intensity to drop is taken. The constituent bate of HAZ area receives line capabilities as solder increase and of warm-up temperature rise and accentuate, but general the tensile strength of its bate area still the floor level requirement of fiducial value of mark of capable person of prep above mother, so the problem of bate of hot influence area of this kind of steel wants technology only proper, do not send the performance characteristics that affects its joint. Nextpage3, pressure vessel is chosen with material of solder of steel of low alloy excel in (1) the welding line metal that the intensity level choice that differs according to rolled steel and intensity of mother capable person comparative is the basic principle that material of solder of this kind of steel chooses, of course, wait for an element according to structure of the use condition of the product, product and plate thickness even meanwhile, the tenacity that considers welding line metal integratedly, plasticity and solder the crack resistance of contact. Want welding line intensity only not under or the floor level of tensile strength of level of capable person of mother of summary prep above is worth can. If the strength of metal of solder material welding line of the choice is exorbitant, the tenacity that will bring about contact, plasticity and crack resistance are reduced, of contact curve function not easy qualification. (2) the cold crack tendency that has different rate as a result of this kind of steel, so, below the premise that waits for intensity principle, the hydrogenous content in controlling solder ability strictly is very important, should choose low hydrogen as far as possible model solder material. When taller to intensity low carbon attune pledges steel solders, more such, should choose to exceed low hydrogen even model solder material, deposit and use what control solder ability strictly. (3) the influence that craft machines after considering solder. Coil to classics heat treatment, heat needing after solder (hot turn) weldment, metal of welding line of Lv of take an examination endures high temperature to handle function the influence of mechanical to its function, sex of He Ren of the intensity that should assure to the demand still is had after heat treatment of classics of welding line metal, plasticity. For example, to the solder burying arc of the 16MnR steel with common pressure vessel, choose H10Mn2 welding wire usually + HJ431 welding flux can. But the welding line of the makeup that seal a head that leaves punch to classics normalizing temperature requiring after solder, its solder material is chosen should raise first gear appropriately, use H08MnMo welding wire + HJ431 welding flux, can offset its intensity loss. 4, pressure vessel solders with steel of low alloy excel in point (1) the solder ability that choose low hydrogen or exceeds low hydrogen tall tenacity, and take stoving seriously, save and of groove clear, in order to reduce the diffusible hydrogen in welding line. (2) what affect area of area thick any crystalline substance to prevent heat is fragile change, should notice to had not used big line energy commonly. When to containing carbolic quantity to slant the 16MnR steel of floor level solders, solder wiring energy does not have rigid limitation, because this kind of steel solders hot influence area is fragile change the trend lesser, but the steel that changes an element to containing the microalloy such as vanadium, niobium, titanium, should choose lesser solder wiring energy. (3) taller to carbon and alloying element content, succumb the steel of low alloy excel in with higher also intensity, be like 18MnMoNbR, because temper by dipping in water of this kind of steel is hard the liability is bigger, want to consider its to heat up the overheat liability that affects an area again, be in choose lesser line capabilities while, add the seasonable postheat measure after the warm-up before solder, solder even. (4) solder when low carbon moves qualitative steel, maintain good tenacity to make heat affects an area, make welding line metal has higher intensity to have good tenacity again already at the same time, this gets with respect to metal of requirement welding line acicular ferrite organization, and this kind of organization is only below faster cooling condition ability is obtained, want to control solder wiring energy strictly for this, do not recommend the welding rod that uses big diameter and welding wire, and should use much method multilayer narrow solder path solder, do not make as far as possible transverse wobbly carry means. To prevent the generation of cold crack, warm-up needs before solder, but should control warm-up temperature strictly, warm-up temperature is exorbitant, can make heat affects an area cooling rate is too slow, produce martensite inside this area thereby + austenite mixture organization and substance of thick shellfish family name, make intensity drops, tenacity addle. The lowermost warm-up temperature that asks highest warm-up temperature does not get prep above to recommend commonly adds 50 ℃ . The method that uses microtherm warm-up to add postheat can prevent low carbon to move qualitative steel to produce cold crack already, can be reduced again or eliminate warm-up temperature exorbitant brought adverse effect. (5) strengthen to soldering the nondestructive of contact detects, sensitive to reheat crackle steel is planted, should want to do ray in PWHT around or supersonic detect. 5, steel of low alloy excel in pressure vessel solders example diameter is 2000mm, the wall is large the amortize canister that is 32mm, housing material is 16MnR character, its are main bear the welder that presses welding line art see next tables. Amortize canister welder position of welding line of number of art watch welding line solders the method solders material specification O1A1, O2A1 seals a flat-fell seam housing of 1A1 of double-faced SAWH08MnMo+HJ431 ① , 2A1, B1, B3 even if, annulus seams annulus of housing of B2 of double-faced SAWH10Mn2+HJ431 ② (: ① seals head flat-fell seam to solder below flat condition after finishing, need ℃ of repass 950 ~ 1000 strike out look has after heating, reason flat-fell seam wants those who pass Ac3 above temperature to heat, the mechanical function of welding line depends on not only chemical composition, and with the organization of welding line condition has very big concern. Although the quantity containing carbon of welding line wants to compare mother capable person a lot of lower, but because solder,be process of a local heating, cooling rate is very old, because this welding line appears,be a kind columnar the special supersaturation of brilliant coins an organization, among them a few the solid dissolve aggrandizement that martensite basically relies on carbon exists, and the substructure of low carbon martensite exists a lot of wrong, the carbon of the solid dissolve of supersaturation collects fault of v/arc be on the throne all round, removing a hammer to plunge into a wrong action, make a fault be hard to move, martensite is out of shape not easily and present the action of aggrandizement welding line. After the temperature that passes Ac3 above heats, welding line is organized from columnar brilliant became brilliant waiting for an axis, broke former substructure position, cloy and degree are reduced, the action of solid dissolve aggrandizement of its carbon also was reduced subsequently, so intensity of certainly will welding line is reduced. The welding line strength that causes to remedy afore-mentioned situations is reduced, adjust the chemical composition of welding line only, use alloying element is a few morer, the welding wire of intensity high first gear will solder hot pressing seals head flat-fell seam. Seam welding of vertical, annulus receives ② housing the condition is good, considering board large element, from improve efficiency, assure to solder quality sets out, choose double-faced the solder that bury arc, welding wire ah wait for intensity principle to choose. ③ equipment folds greatly welding line, considering equipment element, it is more difficult that welding line uses the solder that bury arc inside, reason inside uses welding rod arc welding, outside outer shroud of travel of the reentry after side uses carbolic arc to enrage dig clear root seams the solder that bury arc. B2 welding line occupies manhole closer, reason is his big shut welding line. ④ manhole take-overs to be seamed with manhole flange annulus, because manhole diameter is bigger, reason uses welding rod arc welding to undertake double-faced solder. To manhole, small take-over with housing fillet weld, mix in view of appearance of this place welding line solder condition, choose welding rod arc welding to undertake double-faced solder commonly. ⑤ take-overs to small diameter annulus is seamed, as a result of can bosseyed solder, want to assure quality again, choosing TIG solder render is the method that makes sure welding line quality is the most effective. TIG-50 is solder material brand, model of its solder material is ER70S-G (AWS A5.

18) . ⑥ saddle solder with housing fillet weld is belonged to blame bear press welding line, use extremely fused gas protects solder (protective gas is pure CO2) , efficiency is tall, welding line figuration is good. TWE-711 is solder material brand, model of its solder material is E71T-1(AWS A5.

20) . CNC Milling CNC Machining