Chrome-molybdenum steel pressure-bearing thermal strength steel welding rod used in low-temperature environment of-30 DEG C

Abstract

The invention relates to the related field of welding materials, in particular to a chromium-molybdenum steel pressure-bearing thermal strength steel welding rod used in the low-temperature environment of-30 DEG C. The deposited metal of the welding rod is composed of, by mass, 0.06% of C, 0.70% of Mn, 0.30% of Si, 1.20% of Cr, 0.50% of Mo and the balance Fe. A Mn-Cr-Mo alloy system is adopted, a proper amount of microelements are added, and a slag system is improved, so that the low-temperature impact toughness of weld metal can be better stabilized, and the welding process performance can be better improved.

Description

Technical Field

[0001] The present invention relates to the field of welding materials, in particular to a chromium-molybdenum steel pressure-bearing heat-resistant steel welding rod for use in a low-temperature environment of -30°C. Background Art

[0002] In recent years, with the improvement of national production levels, the mechanical and environmental requirements for steel plates have gradually increased. Currently, domestic heat-resistant steel for welding in low-temperature impact environments is mainly imported. The impact energy of heat-resistant steel deposits at low temperatures is a significant challenge in meeting the requirements of pressure-bearing equipment.

[0003] Therefore, it is necessary to develop a heat-resistant steel welding rod that can meet the pressure requirements of the deposited metal impact energy in a low-temperature environment. Summary of the Invention

[0004] The object of the present invention is to provide a chromium-molybdenum steel pressure-bearing heat-resistant steel welding rod for use in a low-temperature environment of -30°C, so as to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a chromium-molybdenum steel pressure-bearing heat-resistant steel welding rod for use in a low-temperature environment of -30°C, comprising a welding core body and a coating, wherein the material and component percentages in the welding core are as follows: C is 0.05-0.12%, Mn is 0.50-0.90%, Si≦0.60%, Cr is 1.00-1.50%, Mo is 0.40-0.65%, S≦0.008%, P≦0.010%, and the rest The amount of Fe is 27%, and the total amount ratio of each component is 100%; the material and percentage of the component of the coating are: marble 37%, fluorite 27%, silicon micropowder 4%, CMC 0.7%, soda ash 0.7%, nickel powder 0.4%, ferrosilicon 6%, chromium ferronitride 1%, rare earth oxide 0.5%, titanium dioxide 0.5%, sodium alginate 0.2%, amorphous graphite powder 0.2%, zirconium dioxide 1%, ferrotitanium 1%, and the balance is manganese alloy, chromium alloy and molybdenum alloy.

[0006] Preferably, the deposited metal has a tensile strength of 550-670 MPa, a yield strength of ≥460 MPa, and an impact energy of ≥54 J at -30°C.

[0007] Preferably, a method for preparing a chromium-molybdenum steel pressure-bearing heat-resistant steel welding rod for use in a low-temperature environment of -30°C comprises the following steps:

[0008] Step S1: First, the staff places all the raw materials for making the medicine coating in a mixing container and stirs them thoroughly to obtain a mixed powder. After stirring, the humidity of the mixed raw materials is tested to see if it exceeds the preset humidity. If it is lower than the preset humidity, water glass is added to mix it. On the contrary, if it is higher than the preset humidity, the raw materials are added and stirring is continued until the preset humidity is reached.

[0009] Step S2: agglomerate the mixed powder, apply the agglomerated powder to a selected specific welding core, and coat the welding core with a coating to form a welding rod;

[0010] Step S3: The welding rod in step S2 is baked at low temperature and high temperature to form a usable welding material, which is then packaged, inspected and shipped to form a product.

[0011] Preferably, the concentration of the water glass is 41.542.5 degrees Baume; and the potassium-sodium ratio of the water glass is 23:1.

[0012] Preferably, the temperature of the low-temperature baking is 60-100°C, and the temperature of the high-temperature baking is 350-380°C.

[0013] Compared with existing technologies, the present invention offers the following advantages: It utilizes the commonly used Mn-Cr-Mo alloy system and appropriately adds trace elements to enhance and stabilize the low-temperature impact toughness of the weld metal. By adjusting the composition of the welding wire over multiple batches, the weld metal's properties meet the strength requirements of 55kg steel and the low-temperature impact toughness requirements at -30°C. The weld metal's strength is controlled by C, Mn, and Cr, while the impact toughness of the weld is enhanced by controlling the content of Ti, Ni, and trace elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the preparation process of the present invention. DETAILED DESCRIPTION

[0015] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0016] Example 1

[0017] See also Figure 1The present invention provides a technical solution: a chromium-molybdenum steel pressure-bearing heat-resistant steel welding rod for use in a low-temperature environment of -30°C, comprising a welding core body and a coating, wherein the material and component percentages of the welding core are as follows: C 0.05-0.12%, Mn 0.50-0.90%, Si ≤ 0.60%, Cr 1.00-1.50%, Mo 0.40-0.65%, S ≤ 0.008%, P ≤ 0.010%, and the balance is Fe, and the total ratio of the components is 100%; wherein the deposited metal has a tensile strength of 550-670 MPa, a yield strength of ≥ 460 MPa, and an impact energy of ≥ 54 J at -30°C.

[0018] The materials and percentages of the coating are: marble 37%, fluorite 27%, silica powder 4%, CMC 0.7%, soda ash 0.7%, nickel powder 0.4%, ferrosilicon 6%, ferrochromium nitride 1%, rare earth oxide 0.5%, titanium dioxide 0.5%, sodium alginate 0.2%, amorphous graphite powder 0.2%, zirconium dioxide 1%, ferrotitanium 1%, and the remainder are manganese alloy, chromium alloy and molybdenum alloy.

[0019] Furthermore, a method for preparing a chromium-molybdenum steel pressure-bearing heat-resistant steel welding rod for use in a low-temperature environment of -30°C comprises the following steps:

[0020] Step S1: First, the staff puts all the raw materials for making the medicine skin into a mixing container and stirs them thoroughly to obtain a mixed powder. After stirring, the humidity of the mixed raw materials is tested to see if it exceeds the preset humidity. If it is lower than the preset humidity, water glass is added to mix. On the contrary, if it is higher than the preset humidity, the raw materials are added and stirring is continued until the preset humidity is reached; wherein the concentration of water glass is 41.542.5 degrees Baume; the potassium-sodium ratio of the water glass is 23:1

[0021] Step S2: agglomerate the mixed powder, apply the agglomerated powder to a selected specific welding core, and coat the welding core with a coating to form a welding rod;

[0022] Step S3: The welding rod in step S2 is baked at low temperature and high temperature to form a usable welding material, which is then packaged, inspected and shipped to form a product, wherein the low temperature baking temperature is 60-100°C, and the high temperature baking temperature is 350-380°C.

[0023] Example 2

[0024] In this embodiment, the pearlite heat-resistant steel welding rod used for pressure-bearing equipment with an operating temperature below 520° C. is composed of a welding core and a coating.

[0025] Take the powder materials of the coating components: 450g marble, 180g fluorite, 30g silica powder, 30g rutile, 6g CMC, 6g soda ash, 3g nickel powder, 8g sodium alginate, 10g titanium dioxide, 3g amorphous graphite, 9g potassium titanate, 20g zirconium dioxide, 13.5g lanthanum oxide, 105g reduced iron powder and 163g manganese alloy, chromium alloy and molybdenum alloy.

[0026] After mixing the above powders evenly, add 200g of potassium sodium water glass with a concentration of 42 degrees Baume, stir and mix evenly, send it into a strip press and wrap it on a high-quality welding core according to the conventional method, then bake it at a low temperature of 95℃ for 2 hours and at a high temperature of 350-360℃ for 1-2 hours to obtain a heat-resistant steel welding rod.

[0027] A current of 155-165A is used, the plate thickness is 20mm, the base material is Q355B, the test plate groove is 10°, the test plate groove is piled with the welding rod obtained in this embodiment, the pile edge thickness is ≥3mm, the root gap is 16mm, and welding is performed in the flat welding position.

[0028] The welding rod obtained in this embodiment (DC reverse polarity welding) was subjected to a welding test. The arc was stable, there was basically no spatter, the slag removal performance was good, and the weld was beautiful.

[0029] The chemical composition of the deposited metal of the welding rod is C: 0.08%, Mn: 0.70%, Si: 0.420%, Cr: 1.25%, Mo: 0.58%, S: 0.006%, P: 0.009%, and the balance is Fe and impurities. The properties of the deposited metal are shown in Table 1:

[0030]

[0031] Table 1

[0032] Example 3

[0033] In this embodiment, the heat-resistant steel welding rod used for welding 55KG grade steel plates is composed of a welding core and a coating;

[0034] Take the powder materials of the coating ingredients: 400g marble, 200g fluorite, 60g silica powder, 50g rutile, 6g CMC, 8g soda ash, 5g nickel powder, 1.3g sodium fluoride, 10g rare earth oxide, 120g reduced iron powder, 2.8g ferrochrome nitride, 2.3g ferrosilicon rare earth, 3.5g titanium dioxide and 158g manganese alloy, chromium alloy and molybdenum alloy.

[0035] After mixing the above powders evenly, add 200g of potassium sodium water glass with a concentration of 42 degrees Baume, stir and mix evenly, send it into a strip press and wrap it on a high-quality welding core according to the conventional method, and then bake it at a low temperature of 95℃ for 2 hours and a high temperature of 360℃ for 2 hours to obtain a heat-resistant steel welding rod.

[0036] A current of 160A is used, the plate thickness is 20mm, the base material is Q355B, the test plate groove is 10°, the test plate groove is piled with the welding rod obtained in this embodiment, the pile edge thickness is ≥3mm, the root gap is 16mm, and welding is performed in the flat welding position.

[0037] The welding rod obtained in this embodiment (DC reverse polarity welding) was subjected to a welding test. The arc was stable, there was basically no spatter, the slag removal performance was good, and the weld was beautiful.

[0038] The chemical composition of the deposited metal of the welding rod is as follows: C: 0.09%, Mn: 0.68%, Si: 0.390%, Cr: 1.230%, Mo: 0.60%, S: 0.005%, P: 0.010%, Ni: 0.15%, and the balance is Fe and impurities. The properties of the deposited metal are shown in Table 2:

[0039]

[0040] Table 2

[0041] Example 4

[0042] In the embodiment of the present invention, a heat-resistant steel welding rod for welding 15CrMo pressure-bearing steel plates is composed of a welding core and a coating;

[0043] Take the powder materials of the coating components: 360g marble, 260g fluorite, 50g silica powder, 60g rutile, 6g CMC, 6g soda ash, 12g lanthanum oxide, 150g reduced iron powder, 0.2g magnesium oxide, 0.8g aluminum-magnesium alloy, 20g ferrotitanium, 1.2g micro-carbon ferrochrome, 30.7g calcined mica and 170g manganese alloy, chromium alloy and molybdenum alloy.

[0044] After mixing the above powders evenly, add 200g of potassium sodium water glass with a concentration of 42 degrees Baume, stir and mix evenly, send it into a strip press and wrap it on a high-quality welding core according to the conventional method, and then bake it at a low temperature of 95℃ for 2 hours and a high temperature of 360℃ for 1 hour to obtain a heat-resistant steel welding rod.

[0045] A current of 150-160A is used, the plate thickness is 20mm, the base material is Q355B, the test plate groove is 10°, the test plate groove is piled with the welding rod obtained in this embodiment, the pile edge thickness is ≥3mm, the root gap is 16mm, and welding is performed in the flat welding position.

[0046] The welding rod obtained in this embodiment (DC reverse polarity welding) was subjected to a welding test. The arc was stable, there was basically no spatter, the slag removal performance was good, and the weld was beautiful.

[0047] The chemical composition of the deposited metal of the welding rod is as follows: C: 0.085%, Mn: 0.65%, Si: 0.440%, Cr: 1.260%, Mo: 0.620%, S: 0.005%, P: 0.008%, and the balance is Fe and impurities. The properties of the deposited metal are shown in Table 3:

[0048]

[0049] Table 3

[0050] As can be seen from Examples 2-4 above, the present invention utilizes a Mn-Cr-Mo alloy system and adds appropriate trace elements to ensure that the weld metal meets low-temperature impact resistance requirements. Furthermore, by gradually adjusting the contents of Mn, Cr, Mo, Ti, and Ni, the weld metal's strength meets technical requirements. Furthermore, by improving the ore powder, the welding rod's excellent welding process performance is ensured.

[0051] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A chromium-molybdenum steel pressure-bearing heat-resistant steel welding rod for use in a low-temperature environment of -30°C, comprising a welding core body and a coating, characterized in that: The materials and percentages of components in the welding core are as follows: C is 0.05-0.12%, Mn is 0.50-0.90%, Si≦0.60%, Cr is 1.00-1.50%, Mo is 0.40-0.65%, S≦0.008%, P≦0.010%, and the balance is Fe, and the total amount ratio of each component is 100%; the materials and percentages of components of the coating are as follows: marble 37%, fluorite 27%, silicon micropowder 4%, CMC 0.7%, soda ash 0.7%, nickel powder 0.4%, ferrosilicon 6%, chromium ferronitride 1%, rare earth oxide 0.5%, titanium dioxide 0.5%, sodium alginate 0.2%, amorphous graphite powder 0.2%, zirconium dioxide 1%, titanium iron 1%, and the balance is manganese alloy, chromium alloy and molybdenum alloy.

2. A method according to claim 1, characterized in that: The deposited metal has a tensile strength of 550-670MPa, a yield strength of ≥460MPa, and an impact energy of ≥54J at -30℃.

3. A method for preparing a chromium-molybdenum steel pressure-bearing heat-resistant steel welding rod for use in a low temperature environment of -30°C according to any one of claims 1-2, characterized in that: The steps include: Step S1, first, the staff puts all the raw materials for making the medicine skin in a stirring container and stirs them fully to obtain a mixed powder. After the stirring is completed, the humidity of the mixed raw materials is tested to see whether it exceeds the preset humidity. If it is lower than the preset humidity, water glass is added to mix it. On the contrary, if it is higher than the preset humidity, the raw materials are added and stirred continuously until the preset humidity is reached; Step S2, agglomerating and pressing the stirred mixed powder, pressing the agglomerated powder onto a selected specific welding core, and wrapping the welding core with a coating to form a welding rod; Step S3, the welding rod in step S2 is baked at low temperature and high temperature to form a usable welding material, and then packaged, inspected and shipped to form a product.

4. The method for preparing a chromium-molybdenum steel pressure-bearing heat-resistant steel welding rod for use in a low-temperature environment of -30°C according to claim 3, characterized in that: The concentration of the water glass is 41.5-42.5 degrees Baume; the potassium-sodium ratio of the water glass is 2-3:

1.

5. The method for preparing a chromium-molybdenum steel pressure-bearing heat-resistant steel welding rod for use in a low-temperature environment of -30°C according to claim 3, characterized in that: The temperature of the low-temperature baking is 60-100°C, and the temperature of the high-temperature baking is 350-380°C.

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