CN109175756A - The technique of F92 valve body and F11 piping dissimilar steel butt welding - Google Patents

Abstract

The present invention relates to the techniques of a kind of F92 valve body and F11 piping dissimilar steel butt welding, F92 valve body and F11 piping carry out dissimilar steel butt welding, solve the poor technological problems of welding performance, grasp the core technology in welding process, the technological specification with oneself characteristic is formed, considerable economic benefit is obtained.F92 steel；Piping material: F11 steel；Welding material: welding wire R31 bottoming, welding rod R307 capping, four kinds of materials are welded into one；Valve is plus piping effect: reducing coal consumption, improves the thermal efficiency, keeps unit reliable for operation, be continuously increased, increase economic efficiency;The poor technological problems of different steel weld performance are solved, the core technology in welding process is grasped.

Description

The technique of F92 valve body and F11 piping dissimilar steel butt welding

Technical field

The present invention relates to metal working process, and particularly a kind of F92 valve body and F11 are piped the work of dissimilar steel butt welding Skill.

Background technique

With the continuous development of China's thermoelectricity cause, super (super-) critical fired power generating unit with more and more, F92 steel is with it Excellent performance plays an important role.Valve inlet adds a piping, plays the role of saving the energy.

The solderability of F92 steel is poor, and cold crack is easy to produce in welding process, and the tendency of delayed crack is also very big.

F11 heat-resisting steel material alloy total amount is high, and heating conduction and welding performance are poor, is easy to appear crackle, therefore the steel welds Before must preheat be heat-treated with postwelding and can be only achieved requirement.

During F92 valve body and F11 piping dissimilar steel butt welding, it is low that there is qualification rates, postwelding crackle and delay The higher problem of the crackle frequency.Solution is to do welding process performance test, is studied, and the pass in welding process is grasped Key technology is continuously improved, and is put the axe in the helve.

Summary of the invention

To solve the above-mentioned problems, the invention proposes a kind of F92 valve bodies and F11 to be piped different steel weld method, F92 valve Body and F11 piping carry out dissimilar steel butt welding, solve the poor technological problems of welding performance, grasp the core skill in welding process Art forms the technological specification with oneself characteristic, obtains considerable economic benefit.

In order to achieve the above object of the invention, the invention proposes following scheme:

F92 valve body and F11 are piped different steel weld method, are characterized in particular in following steps:

Step 1: the material of confirmation valve body is F92 steel.

Step 2: the material of confirmation piping matched with valve body is F11 steel.

Step 3: selecting welding wire model R31；Selecting the diameter of welding rod model R307 and welding rod is Ф 4.

Step 4: baking welding rod.

R307 welding rod: baking temperature is 300 DEG C -350 DEG C, and baking time is 1 hour.

Step 5: valve body preheating temperature is 450-480 DEG C using the pre- heated work pieces in heating tape, preheating time 2 hours, it is piped Preheating temperature is 400-450 DEG C, is preheated 2 hours.

Step 6: welding:

(1) R31 is welded

Valve body is connected with welding wire R31 with piping spot welding first, valve body and piping position is then corrected, is finally carried out with welding wire R31 Backing welding；Welding current 60-90A.

(2) R307 is welded

With R307 welding rod cover welding, 250 DEG C -350 DEG C of interlayer temperature, welding current 140A-160A.

Step 7: post weld heat treatment uses tempering process, temperature is 750 DEG C ± 10 DEG C, keeps the temperature 3 hours；

Step 8: carrying out radiographic inspection to welding position.

Carrying out radiographic inspection to welding position is according to GB3323 " radiography of steel weld seam and egative film grade separation method " Standard is implemented.

The invention has the advantages that valve body material: F92 steel；Piping material: F11 steel；Welding material: welding wire R31 bottoming, weldering R307 capping, four kinds of materials are welded into one；Valve is plus piping effect: reducing coal consumption, improves the thermal efficiency, runs unit Reliably, it is continuously increased, increases economic efficiency;The poor technological problems of different steel weld performance are solved, are grasped in welding process Core technology.

Specific embodiment

For further description manufacturing process of the invention, and production method advantage obtained is used, under Face further description.

One, the basic performance of material:

1, F92 valve body material:

(1) basic performance of F92 steel:

The material of F92 steel is CrMoVW steel, quite domestic 9Cr0.5Mo1.8WVNb, essential element in steel.

(a) vanadium can improve room temperature, medium temperature intensity and heat resistance, increase the structure stability of steel at high temperature, improve The welding performance of low-carbon alloy steel.

(b) chromium can improve the inoxidizability, corrosion resistance and elevated temperature strength of steel.

(c) molybdenum element is mainly the hot-short sexual orientation for improving intensity and inhibiting chromium steel.

(d) alloy carbide of tungsten prevents the crystal grain of steel from growing up, and reduces the superheated susceptivity of steel, the red hardness of material and Temper resistance is improved.

F92 heat-resisting steel material alloy total amount is high, and heating conduction and welding performance are poor, is easy to appear crackle, therefore the steel welds Before must preheat be heat-treated with postwelding and can be only achieved requirement.

(2) chemical analysis and mechanical performance of F92 steel:

A. chemical analysis:

C	Mn	Si	Cr	W	Nb	Mo	V	Ni	N
										0.07-0.13	0.30-0.60	0.50	8.50-9.50	1.50-2.00	0.04-0.09	0.30-0.60	0.15-0.25	≤0.4	0.03-0.07

B. mechanical performance:

Tensile strength (σ b)	Yield strength (σ s)	Elongation percentage (δ)	Shrinking percentage (ψ)	Hardness HB
					620(MPa)	440(MPa)	20%	45%	≤269

(3) welding performance of F92 steel:

F92 steel is the content (0.5%Mo) that molybdenum element is suitably reduced on the basis of F91 steel, while a certain amount of tungsten is added (1.8%W) mentions about 1.5% from the 1% of F91 steel with the molybdenum equivalent (Mo+0.5W) of material, which is also added into micro boron.

Through above-mentioned alloying improvement after compared with other chromium-molybdenum heat resisting steel, the high-temperature corrosion resistance and oxidation susceptibility of F92 steel with 9%Cr steel is similar, but the elevated temperature strength of material and croop property are further increased, while F92 steel also has better than Ovshinsky The anti-low-cycle thermal fatigue performance of body stainless steel (such as 347H).

The carbon equivalent of F92 steel are as follows:

[ C ]=C+Mn/6+ (Ni+Cu)/15+ (Cr+Mo+V)/5=2.17 carbon equivalent is bigger, and the welding performance of metal is poorer.F92 steel With larger cold cracking inclination, when welding, there may be cold cracks, therefore need preheating, postwelding that must be heat-treated before steel weldering.

2, F11 piping material:

(1) basic performance of F11 steel:

The material of F11 steel is martensite type refractory steel, and (CrMo steel) is equivalent to the GB/T307715CrMo of national standard, main in steel Element.

Chromium can improve carbon steel wearability, and steel is made to have good high-temperature oxidation resistance and oxidative resistance dielectric corrosion Effect, and increase the heat resistance of steel.

Molybdenum element can mainly improve the heat resistance and creep strength of steel, can increase the anti-organic acid of corrosion resisting steel and reducing medium The ability of corrosion.

(2) chemical analysis and mechanical performance of F11 steel:

The chemical analysis of a.F11 steel:

C	Mn	Si	Cr	P	S	Ni	Mo
								0.12-0.18	0.40-0.70	0.17-0.37	0.80-1.10	0.035	0.035	0.30	0.40-0.55

The mechanical performance of b.F11 steel:

Tensile strength (σ b)	Yield strength (σ s)	Elongation percentage (δ)	Shrinking percentage (ψ)	Hardness HB
					440(MPa)	295(MPa)	22%	60%	179

3, the material of R31 welding wire:

(1) basic performance of R31 welding wire:

R31 is the Mayari tungsten argon arc welding wire containing Cr1.25%-Mo0.5%-V.Weld metal has excellent plasticity And toughness.Appearance of weld is beautiful, and all-position welding is functional.When usually welding, temperature 250 between weldment need to be preheated and be kept ~ 300 DEG C, postwelding carries out 700 ~ 725 DEG C of temperings.

It is split for welding temperature in 580 DEG C or less boiler heating surface pipes and 540 DEG C or less jet chimney and petroleum Change equipment, the hand tungsten argon arc welding bottoming of high―temperature nuclei chemical machinery (such as 12Cr1MoV, T/P11 steel) and full argon welding.

(2) chemical analysis of R31 welding wire:

C

Mn

Si

Cr

Cu

Mo

V

P

S

Other element total amounts

0.05-0.12

0.75-1.05

0.45-0.70

1.10-1.40

≤0.30

0.45-0.65

0.20-0.35

≤0.025

≤0.025

≤0.50

(3) R31 mechanical performance:

Tensile strength (σ b)	Yield strength (σ s)	Elongation percentage (δ)
			≧540(MPa)	≧440(MPa)	≧17%

4, the material of R307 welding rod:

The characteristics of R307 welding rod:

Feature: R307 is that the pearlitic heat resistant steel electrode containing Cr1%-Mo0.5% of low hydorgew sodium type coating can using DC reverse connection All-position welding is carried out, weldment should carry out preheating and post weld heat treatment appropriate according to design feature.

Purposes: for welding temperature in 520 DEG C of Cr1%-Mo0.5% heat resisting steel below, such as boiler tubing, high pressure-volume Concise equipment of device, petroleum etc., it can also be used to weld 30CrMoSi steel-casting.

The chemical analysis of R307 welding rod:

C

Mn

Si

Cr

P

S

Mo

0.05-0.12

≤0.90

≤0.60

0.80-1.50

≤0.035

≤0.035

0.40-0.65

(3) R307 mechanical performance:

Tensile strength (σ b)	Yield strength (σ s)	Elongation percentage (δ)
			≧540(MPa)	≧440(MPa)	≧17%

Two, welding procedure:

(1) material:

Valve body material F92 is different from piping F11 material, in addition welding rod R307 and welding wire R31, totally four kinds of material welding are completed.

Step:

First valve body and piping spot welding, welding wire R31 bottoming is then used, finally uses R307 welding rod capping, four kinds of materials are welded on one It rises.

(2) technique:

A: welding rod is baked and banked up with earth.

(a) R307 welding rod.

1. baking temperature: 300 DEG C of -350 DEG C of X1h.

2. core diameter: Ф 4

B: valve body, piping preheating:

Valve body preheating: 450 DEG C of -480 DEG C of X2h.

Piping preheating: 400 DEG C of -450 DEG C of X2h.

C: welding:

Weld R31.

Welding wire spot welding is first used, is then corrected, last backing welding.Welding current 60A-90A.

Weld R307:

250 DEG C -350 DEG C of interlayer temperature, welding current 140A-160A.

D: post weld heat treatment:

Tempering temperature is 750 DEG C ± 10 DEG C, keeps the temperature 3h.

Three, it examines:

Radiographic inspection is carried out to welding position, it is real according to the standard of GB3323 " radiography of steel weld seam and egative film grade separation method " It applies.

Due to the finiteness of literal expression, and objectively there is unlimited specific structure, for the common of the art For technical staff, without departing from the principle of the present invention, can also make it is several improve, retouching or variation, can also be with Above-mentioned technical characteristic is combined in the right way；These improve retouching, variation or combination, or not improved by invention Conception and technical scheme directly apply to other occasions, are regarded as protection scope of the present invention.

Claims (2)

1. the technique of a kind of F92 valve body and F11 piping dissimilar steel butt welding, it is characterised in that: it includes the following steps:

Step 1: the material of confirmation valve body is F92 steel；

Step 2: the material of confirmation piping matched with valve body is F11 steel；

Step 3: selecting welding wire model R31；Selecting the diameter of welding rod model R307 and welding rod is Ф 4；

Step 4: baking welding rod:

R307 welding rod: baking temperature is 300 DEG C -350 DEG C, and baking time is 1 hour；

Step 5: valve body preheating temperature is 450-480 DEG C, and preheating time 2 hours, piping preheated using the pre- heated work pieces in heating tape Temperature is 400-450 DEG C, is preheated 2 hours；

Step 6: welding:

(1) R31 is welded

Valve body is connected with welding wire R31 with piping spot welding first, valve body and piping position is then corrected, is finally carried out with welding wire R31 Backing welding；Welding current 60-90A；

(2) R307 is welded

With R307 welding rod cover welding, 250 DEG C -350 DEG C of interlayer temperature, welding current 140A-160A；

Step 7: post weld heat treatment uses tempering process, temperature is 750 DEG C ± 10 DEG C, keeps the temperature 3 hours；

Step 8: carrying out radiographic inspection to welding position.

2. F92 valve body according to claim 1 and F11 are piped different steel weld method, it is characterized in that welding position into Row radiographic inspection is implemented according to the standard of GB3323 " radiography of steel weld seam and egative film grade separation method ".