21/4Cr

9MPa, design ℃ of temperature 516, belong to condition of operating mode of high temperature high pressure. Although my factory has convection of furnace of old production splitting decomposition paragraph experience, but material is given priority to with carbolic steel commonly, and the wall is large be in 12 Mm less than. Solder to what furnace of high temperature high pressure provides data, study more is Cr5Mo and 12CrMoV domestic and internationally, but solder to study to what furnace is in charge of large wall Cr-1Mo less. For reasonable and affirmatory temperature of energy of its solder wiring, warm-up and system of solder postheat processing, because this is right,its undertook discussing. 1 solder method and solder Duan Lu of convection of furnace of material choice splitting decomposition is in charge of chemical composition to see a table 1, mechanical function is σ B=625 MPa, σ S=498 MPa, ψ =44.

1% , HV=193, ak=257 J. Frame on solder the position is secured for the level add fraise, and requirement of welding line exterior is very slashing. The Yu Gao of welding line is not more than 1 Mm, the difference of on any account of solder wave is more than 0.

5 Mm, rear Yu Gao is 0.

5 Mm, flaw detection of ray of welding line 100%X 2 level are acceptable, because this uses manual TIG solder relatively appropriate, choose the welding wire of TIG-2GM brand low-alloy steel that manufactures by ASME SA355-92 standard, its chemistry composition sees a table 1. Express 　 of 1 chemical composition furnace of % elements CSiMnCrMoSP is in charge of 0.

1300.

2500.

6002.

2701.

0300.

0030.

007 welding wire 0.

0850.

3020.

7802.

2401.

0600.

0080.

0052 welder art experiment and analysis 2.

Experiment of 1 warm-up temperature uses Cr-1Mo steel tube, mural thick 27 Mm, the inclined Y that undertakes normal temperature and different warm-up temperature fall strengthen cabined crack resistance to experiment, the experiment solders normative E=10.

2 KJ/cm(I=110 A, u=14 V, v=9 Cm/min) , 48 H of the classics after solder of test welding line is placed, with chromatic flaw detection surface of examination welding line is mixed with times lower optical microscope observes section, its surface and section crackle rate see a table 2. Express surface of ℃ of ／ of temperature of warm-up of result of test of 2 crack resistance to rupture normal temperature of ％ of ／ of rate of crackle of section of the ％ that lead ／ 100.

0100.

010070.

583.

71500.

043.

52000.

00.

02500.

00.

0 　 experiment makes clear, liability of Cr-1Mo steel cold cracking is bigger, as warm-up temperature rise, contact fights cold cracking ability to be able to improve. When ℃ of Tr ≥ 200, cold crack is eliminated entirely, accordingly, choice of temperature of the warm-up before solder can be satisfied in left and right sides of 200 ℃ fight crack a requirement. 2.

Energy of 2 solder wiring interview check is knowable once upon a time, in ℃ of warm-up temperature 200, when E of solder wiring energy is controlled for 10 KJ/cm, welding line does not appear crackle, so, right now E value should be critical value (floor level is worth) . From shape in light of, undertake below this standard root ministry render is mixed the 2nd, three-layer transfers, whole place shapes good, opposite beyond also is tall inside control target range, and the standard of other solder layer is in make contact acquires good integrated and mechanical property should choose as far as possible below premise a few bigger, in order to improve manufacturing efficiency. Accordingly, must decide upper limit of capabilities of a line is worth, choose two kinds of plan to have a test for this: Render of ① 10 KJ/cm standard transfers, 20 KJ/cm normative fill and lid side. Render of ② 10 KJ/cm standard transfers, 30 KJ/cm normative fill and lid side. The sample of these two kinds of plan issues temper of 2 H high temperature via 710 ℃ . Mechanical function mixes the normal temperature that checks contact - the concussion toughness when 50 ℃ . Tensile strength of contact normal temperature all is in 570 ～ 580 MPa, leng Wandou of ° of course 90 is not cracked. Two kinds of plan solder of bond and the welding line area of sample, hot influence area - contrast of result of concussion of 50 ℃ sees a picture 1. Below condition of same heat treatment, reduce solder layer, the result that increases line capabilities makes contact toughness is reduced. This basically is because of E the cooling rate after increasing slows, bring about overheat area grain bulky, toughness becomes poor, cr-1Mo steel has stronger temper fragile change the trend, it has bigger loss to contact toughness. Accordingly, raise temperature of its model clear change more to will not pass by the accretion of E, the toughness reservior of loss connect, so, choose 20 KJ/cm to regard as solder normative upper limit value. Graph the influence of 1 line capabilities to toughness 2.

Document of disposal specification of 3 solder postheat [1] point out, to Cr-Mo steel, temper parameter [P] span is 20.

0 ～ 20.

6, but specific to some kind weldment, have a first-rate [P] value. The Cr-1Mo furnace of thick to the wall 27 Mm provides the heat treatment after solder, [P] the value takes floor 20.

0, heat preservation 2 H, according to type of temper parameter computation, have: [P] 　 of =T(20+lgt) × 10-3 (in 1) type, t is temper temperature, k; T is heat preservation time, h. By type (1) is knowable T=710 ℃ . Receive the effect of head function to understand temper standard to be opposite further, plan is related before using of 1 solder sample reachs 760 ℃ to have high temperature temper in 650 ℃ , 710 ℃ respectively, heat preservation 2 H, undertake function examines again. To make an on-the-spot investigation [P] right - 50 ℃ pounds toughness influence, the hot influence area that in 650 ℃ , 710 ℃ and 760 ℃ these 3 kinds of condition leave pair of sample is done - the V of 50 ℃ breach pounds an experiment, its see a picture as a result 2. Graph the influence of temperature of 2 heat treatment to toughness 2.

4 　 [P] have the tensile test when room temperature drawing and high temperature of 425 ℃ are short to contact to the influence of welding line intensity, its see a table as a result 3, temper parameter [P] the value is taken 20.

0, namely temper temperature is 710 ℃ , it is more appropriate. Temper of connect of 402475/2843 of ／ of 411485/308760538 of ／ of 436507/359710540 of ／ of B650612 of σ of S/ of the σ when ℃ of B425 of σ of S/ of the σ when expressing room temperature of ℃ of ／ of temperature of temper of the function when 3 connect normal temperature and high temperature are short is fragile change sensitivity to examine 3.

Coefficient of X of 　 of concerned coefficient of metal of 1 welding line, J is the main index that measures volume of sensitivity of Cr-Mo steel temper. Document [2] point out, fight temper goodly to make sure welding line has fragile influence ability, the X coefficient of metal of requirement welding line is less than 25 × 10-6, j coefficient is less than 200. For this, right as fragile as temper changed the element with close relationship to undertake chemical composition is analysed, the result sees a table 4. Express temper of 4 welding line 　 of content of element of feeling of fragile Hua Min content of % elements SiMnPAsSnSb 0.

370.

750.

0060.

000 40.

000 90.

001 can get from the data in the watch: X=(10P+5Sb+4Sn+As)0.

01=0.

000 008 　 (2)J=(Si+Mn)(P+Sn)10 000=84.

5 　 (3) is worth twice this all under control index, show what what choose to solder material enough is contented fight temper fragile the requirement that change. 3.

2 temper are fragile change method of assess experiment assess to use Socal No.

1 pace cold curve [2] , see a picture 3. Pass pace cold treatment, make material divides a pace to pass fragile change temperature, cause quickly fragile the condition that change, make its are inside shorter time material is fragile spend an amount bigger. Graph 3 paces cold treatment (temper of material of Cr-1Mo of SC) curve 　 is fragile clear change temperature should satisfy the model that turn requirement leaving type: 　 of ℃ of 38 of ≤ of VTr54+K Δ VTr54 (in 4) type, Δ VTr54=vTr ′ 54-vTr54, VTr  54 handle for temper (the transition temperature when result of concussion of the 54 J after SR) ; VTr54 adds pace cold treatment for temper processing (the transition temperature when result of concussion of the 54 J after SR+SC) ; K is enhance coefficient, take here 2.

0. Issue 710 ℃ temper of 2 H high temperature (of SR) solder after sample and temper again classics pace cold treatment (the sample of SR+SC) , be in respectively 20 ～ - welding line of dirty of 60 ℃ and the V that heat up influence area breach pounds an experiment, curve of temperature of its model clear change sees a picture 4 with the graph 5. The temperature that can see result of concussion of the 54 J after welding line and SR of hot influence area is - 56 ℃ and - 54 ℃ , welding line is clear change around temperature increment to make an appointment with 5 ℃ , then ℃ of Tr54+2 Δ VTr54=-46, hot influence area is so fragile change around temperature increment to be 8 ℃ about, criterion ℃ of Tr54+2 Δ VTr54=-38, these two results all far under control index. Graph 4 welding line are clear change graph of around transition temperature area of 5 hot influences is fragile change curve of around transition temperature ① of 4 epilogue 　 solders to thick fireplace canal, the warm-up before solder is indispensible, when warm-up temperature control is when left and right sides of 200 ℃ , prevent the generation of cold crack effectively. ② is in charge of a level to secure those who increase obstacle position to solder to furnace, control of floor level of solder wiring energy is controlled in 10 KJ/cm, the ministry of welding line root that can gain satisfaction shapes. To fill solder and cover a range, as the accretion that line capabilities upper limit is worth, solder layer decreases, contact normal temperature is mechanical performance change is not apparent, and - toughness of concussion of 50 ℃ shows apparent downtrend. Fight fracture toughness reliably to make sure contact is had, line capabilities control is in 20 KJ/cm is relatively appropriate. Canal of ③ thick fireplace solders the tensile strength when contact normal temperature and high temperature of 425 ℃ are short, those who follow temper temperature rise to all have drop apparently. And - result of concussion of 50 ℃ is in 710 ℃ , namely [P] =20.

0 when indicated highest value, to assure the integrated and mechanical function of contact, reasonable heat treatment standard is [P] =20.

0, namely ℃ of temper temperature 710, heat preservation 2 H. ④ chooses TGS-2CM welding wire, the coefficient of sensibility of fragile Hua Min of welding line all under control index, control of solder wiring energy is in 10 ～ 20 KJ/cm, temper parameter [P] take 20.

0 when, welding line and the temperature of model clear change that heat up influence area are low, after contact pace cold treatment fragile change temperature increment small, contact toughness have in reserve is large, fight temper ability strong, because this uses its below high temperature,safe abundant is spent big, won't produce brittleness to rupture. CNC Milling CNC Machining