CN101214573B - Medium temperature thick-wall WB36/1Cr18Ni9Ti dissimilar steel welding technology - Google Patents

Abstract

The invention discloses an intermediate temperature thick wall WB36/1Cr18Ni9Ti heterogenous steel welding technique relating to a pearlite(P)/ austenite (A) welding technique. The A technique of the invention includes: {1}buttering three layers first at a WB36 steel side by A307 welding rod as an insulating layer; not preheating when welding and carrying through dehydrogenation treatment after welding; a Phi 3.2mm welding rod must be adopted when buttering a first layer to carry through small current welding with a current range of 70 to 90A for reducing dilution on the welding rod; {2} polishing the surface of the buttering layers to 8mm to form a WB36/1Cr18Ni9Ti butt joint form according with the requirement of criterion; {3} using the A307 or A 137 welding rod to fill and the diameter of the welding rod is Phi 3.2mm or Phi 4.0mm; {4} canceling the heat treatment after welding. The invention reduces the manufacture cost and improves the manufacture efficiency simultaneously when ensuring and improving the joint quality of welding. The invention is suitable for intermediate temperature thick wall WB36/1Cr18Ni9Ti heterogenous steel welding.

Description

In gentle and kind wall WB36/1Cr18Ni9Ti dissimilar steel welding technology

Technical field

The present invention relates to a kind of pearlite (P)/austenite (A) dissimilar steel welding technology, particularly a kind of welding procedure of heavy wall WB36/1Cr18Ni9Ti dissimilar steel joint of working under mesophilic condition.

Background technology

In recent years, along with Chinese economic development, to the demand surge of electric power, the supercritical unit of construction and ultra supercritical unit are more and more.A large amount of heavy wall austenite/pearlite (A/P) dissimilar steel problems of working under middle temperature (200～400 ℃) condition has appearred in unit, main feed water pipe road as unit adopts low-alloyed pearlite WB36 steel, flow-through orifice material wherein is the 1Cr18Ni9Ti austenitic stainless steel, has so just produced major-diameter thick-wall A/P dissimilar steel Welding Problems.Compare with the small diameter tube A/P dissimilar steel joint under working in high temperature, this class joint not only size increases, and the operating condition condition is obviously different, though therefore small diameter tube A/P dissimilar steel welding technology comparative maturity (as the existing power industry standard DL/T752-2001 of the People's Republic of China (PRC) " thermal power plant dissimilar steel solder technology rules "), they and be not suitable in the welding of large-diameter pipe heavy wall A/P dissimilar steel joint under the temperature.Consider from aspects such as welding technology optimization and welding, simplification and joint serviceability and safeties in operation, be necessary the welding procedure of the large-diameter pipe heavy wall A/P dissimilar steel under a kind of middle temperature of specialized designs.

Summary of the invention

The purpose of this invention is to provide a kind of in gentle and kind wall WB36/1Cr18Ni9Ti dissimilar steel welding technology, it is the welding procedure that a cover is simplified, optimized, promptly improving and guaranteeing under the prerequisite of WB36/1Cr18Ni9Ti dissimilar steel joint technology and serviceability, reduce the welding production cost, enhance productivity.

The object of the present invention is achieved like this:

Based on the working condition of WB36/1Cr18Ni9Ti joint, be basic design principle to use performance requirement, grasp the weldability of such dissimilar steel joint by theory analysis and experimental study, carry out the optimal design of welding procedure then.

Specifically, the present invention includes the following step:

A technology:

1. use the A307 welding rod three layers of WB36 steel side elder generation buttering as separation layer, not preheating during welding, the postwelding hydrogen that disappears is handled, and in order to reduce the dilution of butt welded seam, must adopt φ 3.2mm welding rod during the built-up welding ground floor, little electric current welding, current range 70～90A;

2. polish the overlay cladding surface to 8mm, form the WB36/1Cr18Ni9Ti butt joint form that meets code requirement;

3. fill with A307 or A137 welding rod, core diameter is φ 3.2mm or φ 4.0mm;

4. cancel post weld heat treatment.

A technology is suitable for the southern area of China's environment temperature higher (above 0 ℃).

B technology:

1. use Inconel 182 welding rods in the buttering of WB36 steel side elder generation, three layers of first buttering are as separation layer, not preheating during welding, and the hydrogen that needn't disappear is handled;

2. handle with the A307 welding rod hydrogen that behind WB36 steel face down bonding, disappears, in order to reduce the dilution of butt welded seam, must adopt φ 3.2mm welding rod during the built-up welding ground floor, little electric current welding, current range 70～100A;

3. polish the overlay cladding surface to 8mm, form the WB36/1Cr18Ni9Ti butt joint form that meets code requirement;

4. fill with A307 or A137 welding rod, core diameter is φ 3.2mm or φ 4.0mm;

5. cancel post weld heat treatment.

B technology is suitable for the northern area of China of environment temperature lower (being lower than 0 ℃).

The present invention has following advantage, characteristics and good effect:

1. in the selection of welding material, Ni-based welding materials such as the existing general whole employing Inconel 182 of technology, the least possible usefulness of the present invention or need not Ni-based welding material, this can reduce cost on the one hand greatly, also avoids occurring serious weld defect such as slag inclusion, incomplete fusion and fire check in addition;

2. the present invention proposes such joint and can cancel preheating, has reduced welding cost and welder's labour intensity;

3. the present invention is based on test data, clearly propose the cancellation post weld heat treatment, greatly reduce welding cost, saved the engineering time, improved welding production efficiency;

4. the present invention has taken into full account the influence of environment temperature.

In a word, the present invention has reduced production cost when guaranteeing and improving quality of weld joint, improved production efficiency, gentle and kind wall WB36/1Cr18Ni9Ti dissimilar steel welding in being applicable to.

Description of drawings

Fig. 1 is that built-up welding separation layer welding bead is arranged schematic diagram;

Fig. 2 is that A technology packed layer welding bead is arranged schematic diagram;

Fig. 3 is that B technology packed layer welding bead is arranged schematic diagram.

The specific embodiment

The workpiece that with thickness is 20mm is the example explanation:

(1) built-up welding separation layer layout and parameter are seen Fig. 1 and table 1.

Table 1 buttering technological parameter

Layer	Number of weld passes	Layer thickness (mm)	Electric current (A)	Voltage (V)
					Ground floor	4	3	75	30
The second layer	5	4	75	30
					The 3rd layer	3	3	75	30

(2) the welding bead layout and the parameter of butt joint filling are seen Fig. 2 and table 2.

Table 2 A137 welding rod packed layer bead-welding technology parameter

Layer	Number of weld passes	Welding current (A)	Weldingvoltage (V)
				Prime coat	1	75～80	30
Ground floor	2	80	30
				The second layer	2	80	30
The 3rd layer	2	80	30

The 4th layer	3	80	30
				The capping layer	3	80	30

Claims (2)

1. gentle and kind wall WB36/1Cr18Ni9Ti dissimilar steel welding technology in a kind is characterized in that comprising the following steps:

1. use the A307 welding rod three layers of WB36 steel side elder generation buttering as separation layer, not preheating during welding, the postwelding hydrogen that disappears is handled, and in order to reduce the dilution of butt welded seam, must adopt φ 3.2mm welding rod during the built-up welding ground floor, little electric current welding, current range 70～90A;

2. polish the overlay cladding surface to 8mm, form the WB36/1Cr18Ni9Ti butt joint form that meets code requirement;

3. fill with A307 or A137 welding rod, core diameter is φ 3.2mm or φ 4.0mm;

4. cancel post weld heat treatment;

Be suitable for the southern area that China's environment temperature surpasses 0 ℃.

2. gentle and kind wall WB36/1Cr18Ni9Ti dissimilar steel welding technology in a kind is characterized in that comprising the following steps:

1. use Inconel 182 welding rods in the buttering of WB36 steel side elder generation, three layers of first buttering are as separation layer, not preheating during welding, and the hydrogen that needn't disappear is handled;

2. handle with the A307 welding rod hydrogen that behind WB36 steel face down bonding, disappears, in order to reduce the dilution of butt welded seam, must adopt φ 3.2mm welding rod during the built-up welding ground floor, little electric current welding, current range 70～100A;

3. polish the overlay cladding surface to 8mm, form the WB36/1Cr18Ni9Ti butt joint form that meets code requirement;

4. fill with A307 or A137 welding rod, core diameter is φ 3.2mm or φ 4.0mm;

5. cancel post weld heat treatment;

Be suitable for the northern area that environment temperature is lower than 0 ℃.

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