Method for controlling dilution rate of corrosion-resistant surfacing layer

Abstract

The invention discloses a method for controlling the dilution rate of corrosion-resistant surfacing layers, which belongs to the technical field of corrosion-resistant surfacing manufacturing, and comprises the following steps: sequentially welding a plurality of corrosion-resistant surfacing layers on a base material by using pulse current, and setting a welding wire as a welding material; the thickness T of the first two corrosion-resistant surfacing layers is set as T = ((ST * Ds) / Sw) * (Ab / Ap) * alpha; wherein the unit of T is mm; st is the welding speed, and the unit is mm / min; ds is the stepping amount, and the unit is mm; sw is the wire feeding speed, and the unit is mm / min; ab is a basic value current, and the unit is A; ap is peak current, and the unit is A; alpha is an adjusting coefficient; according to the method, the thicknesses of the first two corrosion-resistant surfacing layers can be controlled by utilizing actual welding parameters, the qualified corrosion resistance is obtained on the basis of ensuring that the thicknesses of the corrosion-resistant surfacing layers are as thin as possible, the corrosion-resistant surfacing layers are economical and reliable while the quality of the corrosion-resistant surfacing layers is ensured, the welding difficulty is reduced, and the one-time surfacing percent of pass and the production efficiency are improved.

Description

Technical Field

[0001] The invention relates to the technical field of corrosion-resistant cladding manufacturing, and in particular to a method for controlling the dilution rate of a corrosion-resistant cladding layer. Background Art

[0002] At present, the welding manufacturing industry is continuously deepening its business in the fields of oil and gas equipment, electric power industry, aerospace, etc. Among them, corrosion-resistant cladding products occupy an important position in the welding manufacturing field. Corrosion-resistant cladding is generally used for core components to play a role in corrosion resistance and extending the service life of equipment. Once the corrosion-resistant layer is corroded and damaged by the medium, the consequences will be unimaginable.

[0003] In the design of corrosion-resistant cladding process, the thickness of the cladding layer is generally controlled at 3-6mm; in the cladding process, the Fe content (i.e., dilution rate) diffused from the molten base metal to the cladding layer is a parameter indicator that must be considered. This indicator can measure the corrosion resistance of the corrosion-resistant layer and is a key control point; the industry generally requires that the Fe content in the cladding layer 2.5mm or 3mm away from the weld fusion line does not exceed 5% to prove the safety of the cladding layer. The Fe element in the cladding layer diffuses from the base metal to the cladding layer during the welding process, thereby diluting the corrosion-resistant elements in the cladding layer. The degree of this diffusion is mainly affected by factors such as the welding heat input, the thickness of the cladding layer, and the workpiece temperature.

[0004] At present, there is no effective and stable method to control the dilution rate of the cladding layer in the industry. The existing methods mainly rely on experience and a relatively wide range of parameters, which are highly uncertain and have certain quality and safety risks. Therefore, in order to prevent the Fe content in the corrosion-resistant layer from exceeding the standard, many manufacturers have to increase the thickness of the cladding. Since the corrosion-resistant materials used for cladding (usually nickel-based materials) are expensive, increasing the thickness of the cladding layer will increase manufacturing costs and cause great waste.

[0005] Therefore, it is an urgent problem to be solved at this stage to develop and design a method for controlling the dilution rate of the corrosion-resistant cladding layer that can accurately and effectively control the Fe element content in the cladding layer, achieve the same corrosion resistance on the basis of reducing the thickness of the cladding layer, and reduce the welding difficulty and cladding cost. Summary of the invention

[0006] In response to the problems existing in the prior art, the present invention provides a method for controlling the dilution rate of corrosion-resistant cladding layers. The thickness of the first two corrosion-resistant cladding layers can be controlled by utilizing actual welding parameters, so that qualified corrosion resistance is obtained on the basis of ensuring that the thickness of the corrosion-resistant cladding layers is as thin as possible. The quality of the corrosion-resistant cladding layers is guaranteed while being economical and reliable, reducing the difficulty of welding, and improving the qualified rate of one-time cladding and production efficiency.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows: The present invention provides a method for controlling the dilution rate of a corrosion-resistant cladding layer, wherein multiple layers of corrosion-resistant cladding layers are sequentially welded on a parent material using a pulse current, wherein the welding material is set as welding wire; the thickness T of the first two layers of the corrosion-resistant cladding layers is set as: T=((S t *D s ) / S w )*(A b / A p )*α; T is in mm; S t is the welding speed, in mm / min; D s is the stepping amount, in mm; S w is the wire feeding speed, in mm / min; A b is the base current, in A; A p is the peak current, unit A; α is the adjustment coefficient; in the actual welding process, under the premise of a certain welding wire specification, the welding speed S t and step size D s are inversely related to the thickness T of the corrosion-resistant cladding layer, and the wire feeding speed S w It is positively correlated with the thickness T of the corrosion-resistant cladding layer; and during welding, the peak current A p With the base current A b The larger the ratio, the more intense the heat generation, the deeper the melting depth, and the larger the molten pool volume, which leads to the thinning of the thickness T of the corrosion-resistant cladding layer and increases the dilution rate, that is, the base current A. b With peak current A p The ratio is positively correlated with the thickness T of the corrosion-resistant cladding layer and negatively correlated with the dilution rate; on this basis, the adjustment coefficient α is set to adjust the welding speed S t , step amount D s , wire feeding speed S w , Base current A b , Peak current A p The optimal value of the thickness T of the corrosion-resistant cladding layer can be calculated, and qualified corrosion resistance can be obtained on the basis of ensuring that the thickness of the corrosion-resistant cladding layer is as thin as possible.

[0008] As a preferred technical solution, in the flat welding position, α is set to 1.

[0009] As a preferred technical solution, in the horizontal welding position, α is set to 1.2.

[0010] As a preferred technical solution, the peak current time of the pulse current is set to 200ms, the base current time is set to 200mms, and the pulse width ratio is set to 50%.

[0011] As a preferred technical solution, the number of the corrosion-resistant cladding layer is not less than three.

[0012] As a preferred technical solution, the welding method is set to GTAW welding.

[0013] As a preferred technical solution, before welding, the oil, dirt and rust on the surface of the base material are cleaned and removed.

[0014] As a preferred technical solution, after welding is completed, the corrosion-resistant cladding layer is subjected to penetration testing, tensile testing, impact testing, bending testing, intergranular corrosion testing, chemical composition testing and macroscopic cross-section testing.

[0015] As a preferred technical solution, the welding wire is set to ER316L or ERNiCrMo-13, and the diameter of the welding wire is set to 1.2 mm.

[0016] As a preferred technical solution, the total thickness of the multiple layers of corrosion-resistant cladding layers is set to 3-6 mm.

[0017] The beneficial effects of the present invention are as follows: 1. The present invention can calculate the thickness of the first two corrosion-resistant cladding layers using actual welding parameters, thereby effectively controlling the thickness and dilution rate of the corrosion-resistant cladding layers. On the basis of ensuring that the first two corrosion-resistant cladding layers are as thin as possible, corrosion-resistant cladding layers with qualified corrosion resistance can be obtained, thereby effectively reducing the cladding cost.

[0018] 2. The present invention can design the thickness arrangement of the corrosion-resistant cladding layer according to the cladding requirements of different products, which is effective and accurate, and improves the one-time cladding qualification rate and production efficiency.

[0019] 3. The present invention utilizes actual welding parameters to solidify the thickness of the first two corrosion-resistant cladding layers, thereby reducing welding difficulty, achieving stable welding, and ensuring welding quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of a first embodiment of a method for controlling the dilution rate of a corrosion-resistant cladding layer of the present invention; Figure 2 It is a structural schematic diagram of a second embodiment of a method for controlling the dilution rate of a corrosion-resistant cladding layer of the present invention.

[0021] In the figure: 1-base material, 2-corrosion-resistant cladding layer. DETAILED DESCRIPTION

[0022] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings. Embodiment 1

[0023] Please refer to Figure 1, which is a first embodiment of a method for controlling the dilution rate of a corrosion-resistant cladding layer provided by the present invention, wherein a base material 1 is a SA516 Gr.70 carbon steel plate with a thickness of 15 mm, an ER316L stainless steel corrosion-resistant cladding layer 2 is flat-welded on the surface of the base material 1, and the chemical composition of the base material 1 is shown in Table 1; the welding material is set to an ER316L welding wire with a diameter of 1.2 mm, and the chemical composition of the welding material is shown in Table 2.

[0024] Table 1 Chemical composition of SA516 Gr.70

[0025] Table 2 Chemical composition of ER316L

[0026] Before flat welding, the surface of the base material 1 should be cleaned and freed of impurities such as oil, rust, etc., and no preheating is required. The welding process used is motorized hot wire Tig welding with pulse welding. The specific welding process parameters are shown in Table 3. The thickness T of the three corrosion-resistant cladding layers 2 is set as: T = (S t *D s ) / S w )*(A b / A p ), where S t is the welding speed, D s is the step size, S w is the wire feeding speed, A b is the base current, A p is the peak current; since the molten pool is spread horizontally during flat welding, the adjustment coefficient α=1, so that the thickness T of the corrosion-resistant cladding layer 2 can meet the corrosion resistance requirements; finally, the total thickness of all the corrosion-resistant cladding layers 2 is 5.6mm.

[0027] Table 3 Welding process parameters

[0028] After welding, the cladding surface of the base material 1 was subjected to penetration testing, and samples were taken for macroscopic cross-section inspection, intergranular corrosion inspection, bending test, impact test, chemical composition inspection, and tensile test. All experimental results showed that the Fe content in the corrosion-resistant cladding layer 2 met the requirements, that is, the dilution of the Fe element was effectively controlled. At the same time, the quality of the corrosion-resistant cladding layer 2 was guaranteed. The specific experimental results are shown in Table 4.

[0029] Table 4 Corrosion resistant cladding layer test table Embodiment 2

[0030] Please refer to Figure 2, which is a second embodiment of a method for controlling the dilution rate of a corrosion-resistant cladding layer provided by the present invention, wherein the base material 1 is an A182 F22 forging, and an ERNiCrMo-13 nickel-based corrosion-resistant cladding layer 2 is horizontally welded on the inner wall of the base material 1, and the chemical composition of the base material 1 is shown in Table 5; the welding material is set to be an ER ERNiCrMo-13 welding wire with a diameter of 1.2 mm, and the chemical composition of the welding material is shown in Table 6.

[0031] Table 5 Chemical composition of A182 F22

[0032] Table 6 Chemical composition of ERNiCrMo-3

[0033] Before horizontal welding, the surface of the base material 1 should be cleaned and freed of impurities such as oil and rust, and no preheating is required; the welding process used is motorized hot wire Tig welding with pulse welding, and the specific welding process parameters are shown in Table 7; The thickness T of the three corrosion-resistant cladding layers 2 is set as: T = (S t *D s ) / S w )*(A b / A p ), where S t is the welding speed, D s is the step size, S w is the wire feeding speed, A b is the base current, A p is the peak current; because the molten pool is inclined or vertically set during horizontal welding, it is necessary to slightly increase the adjustment coefficient so that the adjustment coefficient α=1.2, which can also make the thickness T of the corrosion-resistant cladding layer 2 meet the corrosion resistance requirements; finally, the total thickness of all corrosion-resistant cladding layers 2 is 6.0 mm.

[0034] Table 7 Welding process parameters

[0035] After welding, the cladding surface of the base material 1 was subjected to penetration testing, and samples were taken for macroscopic cross-section inspection, intergranular corrosion inspection, bending test, impact test, chemical composition inspection, and tensile test. All experimental results showed that the Fe content in the corrosion-resistant cladding layer 2 met the requirements, that is, the dilution of the Fe element was effectively controlled. At the same time, the quality of the corrosion-resistant cladding layer 2 was guaranteed. The specific experimental results are shown in Table 8.

[0036] Table 8 Corrosion resistant cladding layer test table

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for controlling the dilution rate of a corrosion-resistant cladding layer, characterized in that: Multiple layers of corrosion-resistant cladding layers (2) are sequentially welded on a parent material (1) using a pulse current, and the welding material is set as welding wire; the thickness T of the first two layers of the corrosion-resistant cladding layers (2) is set as: T=((S t *D s ) / S w )*(A b / A p )*α; T is in mm; S t is the welding speed, in mm / min; D s is the stepping amount, in mm; S w is the wire feeding speed, in mm / min; A b is the base current, in A; A p is the peak current, unit is A; α is the regulation coefficient.

2. A method for controlling the dilution rate of a corrosion-resistant cladding layer according to claim 1, characterized in that: In the flat welding position, α is set to 1.

3. The method for controlling the dilution rate of a corrosion-resistant cladding layer according to claim 1, characterized in that: In the horizontal welding position, α is set to 1.

2.

4. The method for controlling the dilution rate of a corrosion-resistant cladding layer according to claim 1, characterized in that: The peak current time of the pulse current is set to 200ms, the base current time is set to 200mms, and the pulse width ratio is set to 50%.

5. The method for controlling the dilution rate of a corrosion-resistant cladding layer according to claim 1, characterized in that: The number of layers of the corrosion-resistant cladding layer (2) is not less than three.

6. The method for controlling the dilution rate of a corrosion-resistant cladding layer according to claim 1, characterized in that: The welding method is set to GTAW welding.

7. The method for controlling the dilution rate of a corrosion-resistant cladding layer according to claim 1, characterized in that: Before welding, the oil, dirt and rust on the surface of the base material (1) are cleaned and removed.

8. The method for controlling the dilution rate of a corrosion-resistant cladding layer according to claim 1, characterized in that: After welding is completed, the corrosion-resistant cladding layer (2) is subjected to penetration testing, tensile testing, impact testing, bending testing, intergranular corrosion testing, chemical composition testing, and macroscopic cross-section testing.

9. The method for controlling the dilution rate of a corrosion-resistant cladding layer according to claim 1, characterized in that: The welding wire is set to ER316L or ERNiCrMo-13, and the diameter of the welding wire is set to 1.2 mm.

10. The method for controlling the dilution rate of a corrosion-resistant cladding layer according to claim 1, characterized in that: The total thickness of the multiple layers of corrosion-resistant cladding layer (2) is set to 3-6 mm.

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