Of refractory steel pressure vessel solder

2 ％ are the following. This kind of steel normally with anneal condition or normalizing + temper condition delivers the goods. Be in as a result of alloy content 2.

The low alloy refractory steel under 5 ％ has pearlite + ferrite organization, reason often also calls pearlite refractory steel, be like 15CrMoR. Alloy content offers money status to be body of shellfish family name in the low alloy refractory steel between ％ of 3 ％ ~ 5 + ferrite organization, reason also calls refractory steel of body of shellfish family name, be like 12Cr2Mo1R. The low alloy refractory steel that uses on pressure vessel basically is in order to join chromium and molybdenum element or complementary in order to join a few the creep intensity that the element such as vanadium, titanium will come to to raise steel and constituent stability, often also say so fasten refractory steel for Cr-Mo refractory steel or Cr-Mo-V. Also be in as a result of this kind of steel high temperature resistant while still have fight hydrogen goodly to corrode function, for this, cr-Mo or the low alloy refractory steel that Cr-Mo-V fastens often also call the steel that fight hydrogen. As refractory steel, divide above outside the low alloy refractory steel that already told, still alloy content is in between ％ of 6 ％ ~ 12 in alloy refractory steel, be like 1Cr5Mo, 1Cr9Mo1, be more than the tall alloy refractory steel of 13 ％ with alloy, be like 1Cr17. Because be in pressure vessel,these two kinds of refractory steel do not see more, this section is given priority to with narrating low alloy refractory steel. To make sure refractory steel solders contact mixes all sorts of move corroding that what medium condition issues long-term security in high temperature, high pressure, its solder contact function should be satisfied issue an a few requirement. Of ① connect wait for connect of strong sex refractory steel to should have the strength when basic and as equal as mother capable person room temperature and high temperature are short not only, and more important is to should have the high temperature long-term strength with close of mother capable person. The sex fighting hydrogen of ② connect and fight connect of oxidisability refractory steel to should have the basic and as identical as mother capable person sex that fight hydrogen and high temperature to fight oxidisability. For this, the alloy composition of welding line metal and content should agree basically with mother capable person. The constituent stability refractory steel of ③ connect solders contact is in production process, especially large wall connect will be endured long for many times heat treatment, the effect of high temperature high pressure suffers for a long time in moving process lieutenant general, each area should not produce contact to organize change apparently to reach what cause from this is fragile change or bate. Of ④ connect fight fragile although refractory steel pressure vessel is most,breaking a gender is in high temperature come off work is made, but make when pressure vessel and conduit finishing hind will undertake designing pressure below normal temperature 1.

The hydraulic experiment of 25 times pressure. After installation is overhauled, want to experience hydraulic experiment and cold start-up process. Accordingly, refractory steel solders contact also should be had fight certainly fragile break a gender. The physical homogeneity refractory steel of ⑤ connect solders contact should have basic and as same as mother capable person physics function. The hot coefficient of expansion of welding line metal and thermal conductance should agree basically, can avoid contact to run the thermal stress in the process in high temperature so. Low alloy refractory steel contains the alloying element of certain amount, accordingly it and steel of low alloy excel in have a few identical soldering characteristic, and the medium work environment that because its contain a few special microelement to reach its,differs, so also its solder distinctly characteristic. (1) the rigid of the Cr of main alloying element in refractory steel of low alloy of rigid of temper by dipping in water and Mo temper by dipping in water that can raise steel significantly. Among them the effect of Mo is 50 times bigger than Cr. These alloying element delayed the steel change in cooling process, increased the stability of super-cooling austenite, form complete martensite possibly below higher cooling rate to organize thereby, when for instance 12Cr2Mo1R solders, if solder wiring energy is lesser, plate thickness is bigger and the martensite change that 100 ％ do not produce likely when warm-up solders. (2) cold crack produces the microstructure with hard temper by dipping in water extremely easily as a result of Cr-Mo steel, plus welding line area enough chroma mixes tall diffusible hydrogen to solder certainly leftover stress is collective action, solder hydrogen of contact easy generation sends defer crackle. This kind of crackle is in hot influence area and welding line metal happen easily. The area is being affected in heat is exterior crackle mostly, normally in welding line metal expression is perpendicular at welding line transverse crackle, the solder line that produces possibly also in multilayer welding falls or solder root place. Cold crack is Cr-Mo steel the main risk that in soldering, exists. (3) because this kind of crackle is,eliminate stress flaw when eliminating stress heat treatment, contact is in the crackle that produces below high temperature again, reason calls reheat crackle again. Cr-Mo steel is steel plants reheat crackle sensitivity, sensitive temperature limits is commonly between ℃ of 500 ~ 700. Many test result makes clear, the strong carbide such as the Cr in steel, Mo, V, Nb, Ti forms an element to reheat crackle have very big effect. The elimination that evaluates steel roughly with crackle index PSR normally stress crackle sensitivity. PSR presses type calculates: PSR=Cr ％ + Cu ％ + 2Mo ％ + 10V ％ + 7Nb ％ + 5Ti ％ - 2 when PSR ≥ 0 when, possible generation eliminates stress flaw. But to carbolic content under 0.

The steel of 1 ％ is planted, go up type is not applicable. (4) hot crack is right low alloy refractory steel, people often pays attention to cold crack prevent. Actually, the figuration coefficient that when solder (frit is wide compare greatly with frit) be less than 1.

2 ~ 1.

3 when, solder path center is easy form hot crack. Because narrow and deep pear form solder,this is, low melting point in all brilliant gathers at solder path center, below welding stress action, bring about occurrence hot crack of solder path center. All factors that affect coefficient of solder path figuration can affect the happening of hot crack. (5) steel of temper brittleness Cr-Mo reachs his to solder contact runs a course for a long time in interval of temperature of ℃ of 350 ~ 500 medium happening fragile the phenomenon that change calls temper brittleness. For example some factory 2.

25Cr-1Mo steeliness pressure vessel is after moving 30000h of ℃ of 332 ~ 432, the temperature of 40J brittleness transition of steel from - 37 ℃ rose + 60 ℃ , bring about disastrous brittleness finally to rupture accident. Cr-Mo steel reachs his to solder the temper brittleness sensitivity of contact has kind of two kinds of evaluations: ① X coefficient and J coefficient X= (10P+5Sb+4Sn+As) × 10-2 (the element in type takes the place of with Ppm content, like 0.

01 ％ should take the place of with 100ppm) J= (Si+Mn) (P+Sn) × 104 (the element in type takes the place of with percentage content, like 0.

15 ％ should with 0.

15 generation are entered) of these two coefficient limitting is the ceaseless development as industry and progress rise step by step, 25ppm of ≤ of X of the earliest demand, j ≤ 200, achieve X ≤ 20ppm later, j ≤ 150, till raised a requirement again at present, 15ppm of requirement X ≤ , j ≤ 100. Law of trial of refrigeration of pace of Nextpage ② cent (the pace is cold) law of trial of the refrigeration that divide a pace is refrigeration of pace of the cent after the highest temperature that heats test specimen to set, temperature every fall one class, heat preservation is longer. Purpose of pace cold treatment is the temper brittleness that makes steel generation the largest inside 200 ~ 300 H, the result that passes generation of ability of 2000 ~ 5000 H with equipment of interval of temperature of ℃ of 350 ~ 500 is same. After heating, make rolled steel happening fast temper is fragile change. Undertake to the rolled steel of around of pace cold experiment series is pounded respectively, before scale gives pace cold test, hind temper is fragile the curve that changes rate, delay Min of classics of sample of VTr54 (of brittleness transition temperature certainly.

The corresponding transition temperature when the summer after PWHT is handled is 54J than concussion result) Min of classics of sample of variable Δ VTr54 (.

The) of corresponding transition temperature increment when the summer after cold treatment of PWHT + pace is 54J than concussion result, press type has consideration: American Xue Fulong company is inchoate the target that raise: VTr54 +1.

38 ℃ of 5 Δ VTr54 ≤ (100 ℉) the index that 90 time use 20 centuries generally: VTr54 +2.

38 ℃ of 5 Δ VTr54 ≤ raise those who reach function of material of rolled steel, solder as what ask to equipment security, taller and taller to the requirement of this index, the target that the two hydrogenation reactor that some engineering company was Ning Bo and design of state chemistry limited company 2006 raises is: 10 ℃ of VTr54 ≤ of VTr54 +3 Δ 2, pressure vessel is chosen with material of refractory steel solder (1) as identical as steel of low alloy excel in, the intensity principle such as welding line metal and mother capable person still is the basic principle that solder material chooses low alloy refractory steel, just right now not only the normal temperature strength that should consider welding line metal and mother capable person strong, also want to make intensity of its high temperature does not follow the floor level demand of the value under mark of mother capable person at the same time. (2) to make metal of its welding line has as same as mother capable person performance characteristics, because this asks,content of the chromium of metal of its welding line, molybdenum does not get the floor level that is worth under level of mother capable person. (3) have likewise small temper brittleness to assure welding line metal, the content of the microelement such as the oxygen in answering to limit solder ability strictly, silicon, phosphor, antimonial, stannum, arsenic. (4) to increase the crack resistance of welding line metal, should control solder material to contain carbon mediumly to measure the carbolic content under mother capable person, but should notice, when the amount that contain carbon is too small, can make ferrite form via the heat treatment after long solder, bring about tenacity to drop thereby, accordingly, to the welding line metal of low alloy refractory steel the quantity that contain carbon had better be controlled in 0.

08 ％ ~ 0.

Inside 12 ％ limits, such ability can make welding line metal has higher impact tenacity and the intensity of high temperature creep that comparative with mother capable person. 3, pressure vessel solders with refractory steel point (1) the temperature between warm-up and layer is in of Cr-Mo steel solder the cold crack that mentions in the characteristic, hot crack and eliminate stress flaw, reach the temperature between the layer with warm-up relevant. Generally speaking, answer to raise the temperature between warm-up and layer to avoid the generation of cold crack and reheat crackle appropriately below conditional license. Next watches are all sorts of pair of low alloy refractory steel to recommend the temperature between chosen warm-up temperature and layer, but be united in wedlock to be chosen actually even in equipment production process. Recommend the thermometer between warm-up of chosen low alloy refractory steel and layer to be mixed to warm-up the temperature between the layer, should notice the following: ① is whole solder the temperature between the layer in the process do not answer under warm-up temperature. ② should make sure surface of weldment inside and outside all reachs warm-up temperature of the regulation. ③ to large wall container, before must noticing solder, solder process and solder to the warm-up temperature when the end keeps basically consistent and make temperature of actual measurement warm-up good record. If ④ undertakes integral warm-up expends from time to time not only before container solder and bad news can. Actually, make local warm-up can obtain the result with integral warm-up close, but 4 times what must make sure warm-up area width is more than place solder ply, and do not be less than 150mm at least. The temperature between ⑤ warm-up and layer must be nodded under the Mf of mother capable person (martensite change end nods) , after be being handled via SR when weldment otherwise, rudimental austenite may produce martensite change, among them the hydrogenous transgression of supersaturation can make rolled steel craze, answer like the temperature between the warm-up to 12Cr2Mo1R and top layer under 300 ℃ . When the makings below ⑥ rolled steel undertakes be cuttinged eagerly, similar solder the hot loop of hot influence area, the hard layer of temper by dipping in water of cut brim may become rolled steel to coil make or when punch crack a source. Accordingly, also answer proper warm-up. (2) solder postheat is handled to low alloy refractory steel, the purpose of the heat treatment after solder is to eliminate not only solder leftover stress, and more important is the integrated and mechanical performance that improves an organization to improve joint, include to increase the intensity of high temperature creep of contact and constituent stability, reduce welding line and hardness of hot influence area, still have even if make hydrogen farther transgression produces cold crack with avoiding. Accordingly, in protocol low alloy refractory steel solders when the solder postheat disposal specification of contact, answer to consider following metallurgy and craft characteristic integratedly. The heat treatment after ① solder should assure to seam the improvement that section knits nearly. ② heats temperature should assure to solder the welding stress of contact falls as far as possible low level. The heat treatment after ③ solder should not make mother capable person is reached solder the lowermost limit that each mechanical function drops contact to design a regulation is the following. This often want to solder through be being reached to mother capable person contact undertakes the biggest handle with postheat of solder of the smallest imitate (Max.

PWHT reachs Min.

Each mechanical function after PWHT) detects will decide. ④ reachs reheat crackle tendency as a result of the temper brittleness of refractory steel, the heat treatment after solder should avoid to handle rolled steel temper brittleness in place as far as possible sensitive area and reheat crackle tendency undertake inside the temperature limits of sensitive area. Should set should have inside dangerous temperature limits faster heat speed. Nextpage considers above integratedly 4 characteristics, need makes a disposal specification of appropriate postheat of refractory steel solder, through many experiment, research, derivative parameter of a directiveness, namely rice straps Naerxun (Rarson, Miller) parameter Tp, also call temper parameter. In type of 10-3 of × of Tp= T (20+log T) : T, heat treatment is absolutely temperature, k T, time of heat treatment heat preservation, h can see from inside type, the temperature of heat treatment and heat preservation time decided the discretion that Tp is worth, also affected Cr-Mo steel to solder the intensity of contact and tenacity. Tp cost is too low, the intensity of contact and hardness will be exorbitant and tenacity is inferior, the cost that be like Tp is too high, criterion intensity and hardness can drop apparently, because the precipitation of carbide is mixed,gather to also can make tenacity drops at the same time, accordingly, tp value is in 18.

2 ~ 21.

The 4 put together join forces with can make contact is had better learn function. Of course, have range of parameter of temper of a first-rate to steel of Cr-Mo of avery kind of, like 1.

25Cr-0.

The optimal Tp value of metal of 5Mo steel welding line is 20.

0 ~ 20.

6 between, to 2.

25Cr-1Mo steel, tp value is in its first-rate 20.

2 ~ 20.

6 between. (3) postheat and liability of cold cracking of steel of Cr-Mo of intermediate heat treatment are big, in bringing about the influencing factor that produces crackle, influence head the list of hydrogen, accordingly, after solder (or among stop solder) must instantly disappear hydrogen. Say commonly, the wall of Cr-Mo steel container is thick, rigid big, production cycle is long, solder hind cannot have heat treatment very quickly, be cracked to prevent and stabilize weldment dimension, in advocate welding line (or advocate welding line and housing take-over welding line) the lower than temperature of final heat treatment heat treatment intermediate has after finishing. The postheat temperature of this kind of steel is 300 ~350 ℃ commonly, also a few make an unit take ℃ of 350 ~ 400. Standard of intermediate heat treatment is planted along with steel, the experience of structure, production unit and different, general temperature of intermediate heat treatment is (℃ of 620 ~ 640) 15 ℃ of ± . (4) solder to choose the temperature between temperature of solder wiring energy, warm-up and layer normatively to be affected directly solder the cooling condition of contact, generally speaking, solder wiring energy is bigger, cooling rate is slower, together with companion has the temperature between taller warm-up and layer, can make contact the grain of each area is bulky, intensity and tenacity can be reduced. To low alloy refractory steel, change inside certain limits to solder wiring energy not sensitive, that is to say, range of permission solder wiring energy is wider, become only when line capabilities is too big, just can mix to intensity tenacity has apparent effect, was thought to prevent the generation of cold crack, capabilities of the line when the hope solders does not pass small. 4, refractory steel steel pressure vessel solders example diameter is 500mm, housing Cheng Bihou is 30mm, monitor wall is large the heater that is 16mm, housing material is 15CrMoR character, its are main bear the welder that presses welding line art see next tables. <DIV align=center> Feng Bian Hao </DIV><DIV align=center> Han Feng Wei Zhi </DIV> Jia Re Qi Han Jie Gong Yi Biao <DIV align=center> Han Jie Fang Fa </DIV><DIV align=center> Han Jie Cai Liao </DIV><DIV align=center> Shuo Ming </DIV><DIV align=center>3A1、4A1、B6</DIV><DIV align=center>B2-B5、B7</DIV><DIV align=center>B8、B9</DIV><DIV align=center> Guan Cheng Tong Ti Zong 、 Huan Feng </DIV><DIV align=center> Ke Cheng 、 Guan Cheng Tong Ti Yu Guan Ban Huan Feng </DIV><DIV align=center> Jie Guan Yu Dui Jie Fa Lan Huan Feng </DIV><DIV align=center>GTAW Da Di </DIV><DIV align=center>SMAW Gai Mian </DIV><DIV align=center>H13CrMoA</DIV><DIV align=center>R307</DIV><DIV align=center>①</DIV><DIV align=center>1A1、2A1、B1、B4</DIV><DIV align=center> Guan Cheng Tong Ti Zong Feng </DIV><DIV align=center> Guan Cheng Tong Ti Yu Fa Lan Huan Feng </DIV><DIV align=center>SMAW</DIV><DIV align=center>R307</DIV><DIV align=center>②</DIV><DIV align=center>D1-D6</DIV><DIV align=center> Jie Guan 、 Zheng Ti Fa Lan Yu Fa Lan Gai 、 Guan Ban 、 Ke Ti Jiao Han Feng </DIV><DIV align=center>SMAW</DIV><DIV align=center>R307</DIV><DIV align=center>③</DIV><DIV align=center>D7</DIV><DIV align=center> Huan Re Guan Yu Guan Ban Jiao Han Feng </DIV><DIV align=center>GTAW（ Zi Dong ）</DIV><DIV align=center>H08CrMoA</DIV><DIV align=center>④</DIV><DIV align=center>E1</DIV><DIV align=center> Er Zuo Yu Ke Ti Jiao Han Feng </DIV><DIV align=center>GMAW</DIV><DIV align=center>(CO2 Han )</DIV><DIV align=center>TWE-811B2</DIV><DIV align=center>⑤</DIV> Shuo Ming ： ① carapace Cheng drum diameter is lesser, the solderer cannot be gotten solder inside cylindrical shell, vertical, annulus seams cylindrical shell of reason carapace Cheng can from outside side applies solder. Same, as a result of the reason of respect of this facility construction, the annulus seam welding of cylindrical shell of housing Cheng, monitor and tube plate is received also can from outside side undertakes. As to take-over to be seamed with annulus of butt joint flange, norms take-overs to be φ in this equipment 273 × 12, also cannot apply solder from inside. Above welding line needs bosseyed solder, but should assure quality again, choosing TIG solder render is the method that makes sure welding line quality is the most effective. Seam to annulus of housing Cheng cylindrical shell, also can use GTAW render, SMAW again solder two, next the method of layer of SAW solder the rest. ② although monitor drum diameter is lesser, but its length is very short, cylindrical shell of N-joining of monitor cylindrical shell, monitor and flange annulus seam the requirement that has arc welding of inside welding rod, reason uses welding rod arc welding to undertake double-faced solder. ③ take-overs, the fillet weld equipment of integral flange and flange lid, tube plate, housing folds greatly welding line, mix in view of appearance of this place welding line solder condition, choose welding rod arc welding commonly. ④ heat exchanger tube - the main welding line that tube plate solders is hot exchange equipment, its solder the method has welding rod arc welding, handiwork solder of arc of tungsten pole argon, whole place is automatic argon arc solder. Welding rod arc welding is the earliest use solder method, its characteristic is efficiency tall, but quality is comparative at other should differ for two kinds of methods a lot of, already basically was washed out now. But in certain and special situation, if silk blocks type sky up cold implement, its pipe - tube plate solders must block up through the silk before tube plate board undertake soldering, can use the method that uses welding rod arc welding only at this moment, solder with small diameter welding rod, demand of technology of operation of this pair of solderers is very high, need to undertake grooming technically to the solderer before solder commonly. Use at present the most extensive, quality solders best the method is solder of automatic argon arc. The heat exchanger tube in this equipment - tube plate solders use total position solder of automatic argon arc, solder contact form is fillet weld. Welding wire diameter is 1mm, the solder that fill silk two. ⑤ ear 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-811B2 is solder material brand, model of its solder material is E81T1-B2(AWS A5.

29) . CNC Milling