The distributinging configuration of sulfide solders to SA335 P91 steel the influence of root ministry hot crack

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Summary: Whole to butt joint of pipe of SA335 P91 heat place secures bosseyed solder sample of double-faced figuration welding line undertook metallographic is analysed, electric lens scanning and small area can chart analysis. The result makes clear, content of the S of the solder material that although SA335P91 steel reachs place,uses, P is very low, but if craft choice is undeserved, still can produce crystallization crackle; Crystallization crackle generation basically depended on the low melting point of S in all brilliant compound is in the distributinging configuration of crystal boundary, is not to depend on the absolutely content of S. In the content of S higher case falls, the content of S is high but be opposite in order to nod shape distributinging Yu Jing on the bound of crystal boundary weaken the effect and not apparent, if with velar shape or on the crystal boundary of sulfide consist in that lump content form distributings, bring about the generation of crackle of the crystallization on crystal boundary easily. Keyword: Low frit of crackle of crystallization of SA335 P91 steel in all the efficiency that preface of crystal distributinging pattern improves igneous power plant is a when will solve global environment problem henceforth strong step, using superhigh temperature tall circulation is efficient one of methods that change [1] . To this century the fifties, utility boiler steel tube uses ferrite alloy steel mostly (21/4Cr-1Mo) and austenite stainless steel (the) such as TP304, TP347, but the development as tall parameter aircrew, of boiler temperature and pressure rise further, the function of high temperature creep to steel tube material and fight stress to corroded a respect to raise taller requirement [2] . Below this kind of setting, the United States ever was opposite 1974 much existing material undertook a huge demonstration works, the result makes clear, improve model 9%Cr-1%Mo steel showed outstanding integral performance in the respect such as such as corrosion resistance, weldability, processability, mechanical function. But, in recent years, when a lot of boiler manufactories are using 9%Cr-1%Mo steeliness to make boiler, pressure vessel, the problem that encounters is the problem of cold crack not just, to soldering the hot crack that appears in the process also takes seriously more and more [3-6] . Some oil builds a company to be in production north some is large ethylene revises extend project in, splitting decomposition convection paragraph superheater of extrahigh voltage vapour paragraph be pledge for material with SA335 P91, norms is φ 73.

3 × 9.

53mm, when detecting into travel X ray after solder, discover flaw of existence of halfway solder mouth, bring about a large number of repair, caused bigger effect to time limit for a project. The author is in document [in this project is aimed at in 7] , appear solder root ministry crackle undertook an analysis, think its crackle belongs to crystallization hot crack, point out close analyse element content slants between the brilliant such as the sulfur on the crystal boundary inside the area, phosphor tall, slant analyse is serious and one of main reasons that close the stress with higher area is crackle generation centrally. Accordingly, the article solders key analysis craft parameter organizes crystallization to slant to welding line of SA335 P91 steel the influence of analyse, with period the adjustment that passes craft parameter will rise solder of contact solder quality. 1 solder test data and experiment method 1.

The SA335 P91 steel tube that experiment of 1 test data chooses stays in friendly metal company to produce by Japan, norms is φ 73.

3 × 9.

53mm, if its chemistry component and mechanical function express 1 to show. Solder the method uses solder of manual argon arc, solder material uses England graceful thorough solders especially the ER90S-B9 welding wire of data company, diametical φ 2.

4 Mm, if the chemical component of metal of its frit apply expresses 2 to show. 1.

Test of 2 experiments means uses a canal to add solder of fraise whole place to receiving a level to secure, come from the solder when the position 6 o'clock is suitable above all at 12 o'clock needle position, try place receiving arc after burnish, again from 6 o'clock the position is anticlockwise directional right solder, the electric arc before second half part closes with before half part is made a bit here stay and swing, after waiting for alveolus to close, electric arc continues electric arc of reach 5mm left and right sides receives arc outside derivative groove. Solder speed is 105mm/min, other craft parameter sees a table 3. From document [in the analysis of 7] knowable, solder crackle basically arises to be collected at solder path is being controlled to hand in when solder of root ministry render close alveolus is in. If pursue 1, the graph is shown 2 times. So, examine the area that happens in crackle basically is taken when sampling, after flaw detection of ray of sample classics X, decide the sample classics axial that has flaw and Zhou Xiang definitely hind face of craze of edge of method of the cut that use a line is apart and the firsthand look appearance that should preserve crackle, and the sample of existing to was not being sent crackle is handed in along or so solder collect close alveolus center is interrupted compulsively, use lens of report of XL-30FEG of Holand Hilips company scanning to undertake ray of the fracture surface scanning, DX4i that uses American EDAX firm X respectively next can chart appearance undertakes can microscope of the chart analysis, DMIRM that manufactures with German Leica company attend school undertakes microcosmic metallographic is analysed. Among them can chart analysis basically is small to be being analysed area begs average. 2 tests result 2.

1 can chart analysis result undertakes to parameter of 3 main craft root ministry solders experiment, path of the or so solder in to the render solder of place solder sample is handed in collect close alveolus is in EDAX of place area small area can if result of chart analysis data expresses 4 to show. The chemical component that expresses steel of 1 SA335 P91 and mechanical function (note: ① : Standard; ② : Actual measurement is worth) Table1 Chemical Composition And Mechanical Property Of SA335P91steel Normal Align=center> chemical component (Wt% ) Normal Align=center>Cnormal Align=center>Mnnormal Align=center>Sinormal Align=center>Crnormal Align=center>Monormal Align=center>Vnormal Align=center>Nbnormal Align=center>Ninormal Align=center>Nnormal Align=center>Snormal TEXT-ALIGN of Center" Align=center>P ① : Center" Align=center>0.

08-0.

12 Normal Align=center>0.

30-0.

60 Normal Align=center>0.

20-0.

50 Normal Align=center>8.

00-9.

50 Normal Align=center>0.

85-1.

05 Normal Align=center>0.

18-0.

25 Normal Align=center>0.

06-0.

10 Normal Align=center>0.

40 Normal Align=center>0.

03-0.

07 Normal Align=center> ≤ 0.

01 Normal Align=center> ≤ 0.

Normal Align=center>0.

10normal Align=center>0.

48normal Align=center>0.

39normal Align=center>8.

98normal Align=center>0.

93normal Align=center>0.

21normal Align=center>0.

08normal Align=center>0.

40normal Align=center>0.

06normal Align=center>0.

0035normal Align=center>0.

016normal TEXT-ALIGN of Center" Align=center> mechanical function: B /MPanormal Align=center> σ : S /Mpanormal Align=center> σ : 5(%)normal Align=center> δ : Center" Align=center>Ak(J)(+20 ℃ ) Normal Align=center>HBnormal TEXT-ALIGN of Center" Align=center> ≥ : 415normal Align=center> ≥ : 20normal Align=center> ≥ : 41normal Align=center> ≥ : 250normal Align=center> ≤ : Center" Align=center>677 Normal Align=center>501 Normal Align=center>34 Normal Align=center>87 Normal Align=center>178 Normal Align=center> watch (quality percentage, % ) Normal Align=center>Table2 Chemical Composition Of Deposited Metal Of Welding Wire Normal Align=center>Cnormal Align=center>Mnnormal Align=center>Sinormal Align=center>Crnormal Align=center>Monormal Align=center>Vnormal Align=center>Nbnormal Align=center>Ninormal Align=center>Nnormal Align=center>Snormal Align=center>Pnormal Align=center>Alnormal > ① Normal Align=center>0.

08-0.

13 Normal Align=center>0.

40-0.

80 Normal Align=center>0.

15-0.

30 Normal Align=center>8.

00-9.

50 Normal Align=center>0.

80-1.

1 Normal Align=center>0.

15-0.

25 Normal Align=center>0.

03-0.

08 Normal Align=center>0.

40-0.

8 Normal Align=center>0.

03-0.

07 Normal Align=center> ≤ 0.

01 Normal Align=center> ≤ 0.

01 Normal Align=center> ≤ 0.

04 Normal TEXT-ALIGN of Center" Align=center> ② : Center" Align=center>0.

10normal Align=center>0.

50normal Align=center>0.

25normal Align=center>8.

70normal Align=center>1.

00normal Align=center>0.

20normal Align=center>0.

05normal Align=center>0.

6normal Align=center>0.

03normal Align=center>0.

006normal Align=center>0.

008normal Align=center> ≤ 0.

01normal Align=center> pursues Normal Align=center>Fig 1 Region Of Crack Occurring Normal Align=center> pursues 2 or so solder hands in collect alveolus to close Normal Align=center>Fig 2 Region Of Hole Closednormal Align=center> expresses parameter of craft of 3 typical experiments and result Normal Align=center>Table3 Typical Test Parameters And Results Normal TEXT-ALIGN of serial number of Center" Align=center> experiment: Center" Align=center> solders electric current (A) Normal Align=center> warm-up heats up temperature (℃ ) Normal Align=center> alveolus (S) Normal Align=center>EDAXS%(w%) Normal Align=center> whether craze Normal Align=center>2# Normal Align=center>100 Normal Align=center>170 Normal Align=center>0 Normal Align=center> -- Normal Align=center> denies Normal Align=center>5# Normal Align=center>130 Normal Align=center>170 Normal Align=center>5 Normal Align=center>6. 2270 Normal Align=center> denies Normal Align=center>8# Normal Align=center>150 Normal Align=center>170 Normal Align=center>10 Normal Align=center>0. 5090 Normal Align=center> cracks Normal Align=center>12# Normal Align=center>130 Normal Align=center>170 Normal Align=center>10 Normal Align=center>0. 7252 Normal Align=center> cracks Normal Align=center>14# Normal Align=center>150 Normal Align=center>250 Normal Align=center>5 Normal Align=center>0. 3876 Normal Align=center> denies Normal Align=center>18# Normal Align=center>150 Normal Align=center>250 Normal Align=center>5 Normal Align=center>10. 584 Normal Align=center> denies Normal Align=center>21# Normal Align=center>150 Normal Align=center>170 Normal Align=center>15 Normal Align=center>3. 2290 Normal Align=center> is cracked 2.

2 microcosmic metallographic analyse Normal LINE-HEIGHT of microstructure of welding line of 3 2# of Center" Align=center> graph: 12pt; TEXT-ALIGN: Center" Align=center>Fig.

3Graph of Microstructure Of 2# Weld Seam closes the microstructure of alveolus place pursues below the 3 sample as welded that are the 2# craft preparation with executive lesser standard, solder electric current and alveolus retention period are briefer, reason grain is finer, attrib wattle martensite bundle shorter and narrow, and the graph is a watch 4 3 in the microstructure graph that 21# craft sample closes below as welded alveolus is in and crackle form appearance, apparent, what its grain dimension should show 3 times than the graph is big, martensite bundle grow already thick and extremely directional strong. Normal LINE-HEIGHT of microstructure of crackle of welding line of 4 21# of Center" Align=center> graph: 12pt; TEXT-ALIGN: Center" Align=center>Fig.

4Microstructure Of 21 # Weld Crack 2.

In sample of 5# of result of analysis of lens of 3 scanning report, 8# , 18# , 21# , 5# and 18# do not have craze, make sample from path of or so solder with percussive method collect close alveolus place rushs, and sample of 8# , 21# has flaw, criterion from crackle face one divides into two, issue observed microcosmic form appearance in scanning report lens respectively, its model feature is like graph 5-6 place to show. Normal Align=center> expresses EDAX of 4 representative sample to analyse detailed result (unit: Wt ％ ) Normal Align=center>Table.

4 Results Of EDAX For Typical Specimens Normal >C Normal >S Normal >Cr Normal >Mn Normal >Fe Normal >Al Normal >Ti Normal >Ni Normal >5# Normal >2.

153 Normal >6.

227 Normal >11.

817 Normal >12.

089 Normal >68.

199 Normal >18# Normal >3.

603 Normal >10.

584 Normal >12.

781 Normal >18.

777 Normal >44.

608 Normal >1.

888 Normal >2.

022 Normal >8# Normal >5.

359 Normal >0.

509 Normal >10.

698 Normal >0.

723 Normal >82.

627 Normal > Normal > Normal > Normal >21# Normal >1.

804 Normal >3.

229 Normal >8.

510 Normal >0.

192 Normal >83.

950 Normal > Normal > 2.

315 Normal Align=center> graph breaks Normal Align=center>Fig.

5The Fracture Pattern Of 18# Weld Seam Normal Align=center> graph breaks Normal Align=center>Fig.

6The Fracture Pattern Of 21# Weld Cracknormal >3 analysis and discussion Normal > can see from the test result in front: Normal >1) or so solder is handed in collect close alveolus is in whether craze and solder closely related the standard, basically depend on solder electric current and alveolus close manage retention period, the sample of craze is I slants big or it is Thole grow or slanting is both slants big. Normal >2) look from EDAX result, on the whole, the opposite content of the sample S of craze is higher, this explains, solder the generation of hot crack was concerned with the content of the S on the crystal boundary inside welding line, the S content of the steel tube that experiment place chooses and welding wire is low-down, so the S on crystal boundary is to pass what make up analyse to gather and come necessarily [8-10] . Normal > expresses material of the part on the 4 section that showed these 4 representative sample can chart result, sample of 5# , 18# arises without crackle, sample of 8# , 21# has crackle generation, look from the appearance of form of factitious fracture surface of 18# sample, it is typical ductile fracture surface, bottom of nest of pliable but strong has globose field trash, undertake to its can chart analysis, the result shows it is vulcanization manganese field trash, its melting point dot is 1610 ℃ , this kind with bulbiform (grain shape) the sulfur element that the vulcanization manganese field trash that distributing exists, do not have any contribution to the formation of crystallization crackle and generation, arise without crackle consequently, return the sulfide that discovered high melting point to form elemental Ti in the field trash of bottom of nest of pliable but strong at the same time, this is farther confirm the viewpoint of the sensitivity that sulfide of high melting point forms an element to be able to reduce hot crack. And the crackle surface of sample of 8# , 21# , through can chart analyses discovery, the low melting point with many existence in all crystal forms elemental S, Ni, Fe to wait reach its to facilitate elemental C, they are the low melting point on FeS-Fe and Fe-S crackle face in all crystal Yan Mianmian rises and fall distributing, exterior brightness, edges and corners is pliable, into the group agglomerate, configuration nature, this explains its are caky time is long. Soldering below the condition with material and mother same capable person, some discovered these welding line that are analysed crackle, some are done not have however, investigate its reason, basically be to mix solder craft parameter is concerned, have the welding line that crackle produces, the generation of its crackle basically is component slants analyse is quite serious, this concerns with size of grain of welding line austenite again close, metallographic analysis proved this as a result. The generation of retention period Thole to crystallization crackle affects aperture the biggest, increase when Thole especially when, the attrib wattle martensite in discovering welding line is organized bundle lengthen coarsen, extremely directional strong, this brings about component to slant necessarily analyse aggravate, below the premise that satisfies in other condition then, generation crackle. From the watch 4 indication results and its analysis make clear, solder through optimizing a choice standard, electric arc is in what path of or so solder closes alveolus is in 5 seconds less than to stay is the significant step that prevents hot crack generation. Normal >4 conclusion Normal >1) although SA335P91 steel and the solder capable person that its choose contain the impurity such as S, P to control the lower limit that sets in the standard strictly, but if solder normative choice is undeserved, still can cause serious component to slant analyse causes crystallization crackle thereby. Normal >2) crystallization crackle basically depended on low melting point in all the distributinging configuration of brilliant sulfide is not pure depend on the absolutely content of S. The content of S is high but with (Mn, fe)S is opposite on bound of distributinging Yu Jing of record of brilliant form drop in all of crystal boundary weaken the effect and not apparent, and the form that submits content of velar shape, lump with the form of FeS-Fe and FeS distributings to be met on trident crystal boundary weakened crystal boundary adhesion badly, reduced crystal boundary to rupture intensity, bring about the generation of crystallization crackle the most easily. CNC Milling CNC Machining