TWI496647B - High - carbon base metal with hard surface repair welding consumables and high - carbon base metal used in hard surface repair method - Google Patents

Description

Hard surface repairing welding material for high carbon base material and hard surface repairing method for high carbon base material

The invention relates to a welding consumable, in particular to a welding consumable which is applied to hard surface welding repair without causing welding hot cracking.

Related research and development of metallic materials is increasingly advanced, and metal materials generally refer to metals or alloys used in the manufacture of various structures in the industry. Alloys often refer to materials in which two or more metals or metals are combined with non-metals and have metallic properties. Generally, metal materials have the following common characteristics: (1) good conductors of electricity and heat; (2) plastic processing deformation ability, ductility and malleability, so they are widely used in mold processing, machinery manufacturing, foundry industry, and In the industrial industry, because the surface cleanliness of metal materials is currently improved, the welding method and materials between the metal materials become an important issue.

Rollers commonly used in steel mills, the higher the carbon content, the higher the hardness, but the higher the carbon content (usually more than 0.45%), the less welding material that can be used, and As a hard-faced weld bead, hot cracking usually occurs. When it is used for a long time, the roller may break, which is very dangerous and must be shut down to cause economic loss.

High-carbon base materials such as S60C, S70C, S80C, S85C, S90C, and SUJ2 in the prior art rolls have a carbon content of more than 0.6 to 1.2%, and are known to have problems such as thermal cracking or unbearable use. It can not be directly scrapped through secondary repair and repair, which is economical and economically unfriendly for users. It can be seen that there is still a lack of a buffer that can be used for high carbon content base materials and is not prone to hot cracking problems. Layer welding consumables.

The present inventors have in view of the fact that the high-carbon base material of the prior art does not have a corresponding repairing method, and is treated as a scrapping treatment once a crack or the like is generated, which is relatively environmentally friendly and costly, and invents a hard surface repairing welding material, which can be The welding repair applied to the high carbon base material is the object of the present invention.

In order to achieve the foregoing object, the technical means adopted by the present invention provides a hard surface repair welding material which is mainly composed of carbon, molybdenum and iron elements, wherein the carbon element weight percentage is between 0.02 and 0.10%; and molybdenum element The weight percentage is between 1.4 and 3%.

Preferably, a hard surface repairing consumable is an alloy comprising the following elements: a carbon element weight percentage of between 0.02 and 0.10%; and a manganese element weight percentage of between 1.0 and 3.0%; and a niobium element weight percentage Between 0.3 and 1.0%; and the chromium element weight percentage is between 0.6 and 3.5%; and the molybdenum element weight percentage is between 1.4 and 3%; and the sulfur element weight percentage is 0.03% or less; and the phosphorus element weight percentage is Below 0.03%; and the rest of the ingredients are iron.

Preferably, the carbon element weight percentage is 0.03%; the manganese element content percentage is 2.1%; the cerium element content percentage is 0.6%; the chromium element content percentage is 0.7%; the molybdenum element content percentage is 3%; the sulfur element content percentage is 0.03% or less; and the percentage of the phosphorus element content is 0.03% or less.

The hard surface repair welding material can be applied to the welding repair of the high carbon base material.

The hard surface repair welding material has good resistance to solder thermal cracking.

The hard surface repairing welding material has good pitting resistance.

The hard surface repairing welding material has a Vickers hardness of between 310 Hv and 370 Hv when the temperature is heated to about 550 °C.

By the hard surface repair welding material of the invention, the following advantages and effects can be achieved:

1. The hard surface repair welding material of the invention can withstand the dilution of the high carbon base material, so that the high carbon base material can be hard surface welded and repaired at an appropriate timing without being scrapped, which can greatly reduce the cost to avoid waste.

2. The hard surface repair welding material of the invention has good molten gold hardness, pitting corrosion resistance, temper softening resistance, impact resistance and resistance to solder thermal cracking of high carbon base materials.

The present invention is directed to a hardfacing repairing material, and the specific embodiments thereof are as follows, but it should be understood that the examples are for illustrative purposes only and are not to be considered as limiting of the invention.

The hard surface repairing welding material of the present invention, hereinafter referred to as RolClad, comprises carbon, manganese, cerium, chromium, molybdenum, sulfur and phosphorus, and the weight percentage of each element is as shown in Table 1:

The invention also adopts a commercially available hard surface repair welding material as the control group 1 and the control group 2, the control group 1 contains carbon, manganese, strontium, chromium, molybdenum, sulfur and phosphorus, and the control group 2 contains carbon, Manganese, bismuth, molybdenum, sulfur and phosphorus, the composition of each element of the two control groups are shown in Table 2:

The welding method referred to in the following embodiments of the present invention is a submerged arc welding method known to those skilled in the art, and the welding parameters are represented by current/voltage/welding height/welding speed, and welding parameters. As described in the examples below.

Example 1

Pitting resistance test

The RupClad, Control 1 and Control 2 of the present invention were subjected to pitting resistance equivalent calculation, and the pitting resistance equivalent was calculated by the following formula.

PRE _N =Cr+3.3Mo+30N

The results showed that the pitting resistance equivalent of the RolClad of the present invention was between 12.09 and 61.21, while the pitting resistance equivalent of the control group 1 was 11.02 and the pitting resistance equivalent of the control group 2 was 3.9. From this result, it was found that the pitting resistance was observed. RolClad was superior to control group 1 and control group 2.

Comparing the weight percentage differences of the elements of RolClad, control group 1 and control group 2, it can be seen that the peat corrosion resistance of RolClad is better than that of control group 1 and control group 2 because of the high content of molybdenum element.

The experimental conditions for the pitting resistance test are as follows:

Reaction ambient temperature; 30 ° C;

Reaction environment humidity: 80%;

Welding parameters: 400A/30V/ESO 30mm/40cpm;

Welding preheating temperature: 250 ° C ~ 400 ° C;

Use welding consumables: RolClad and control 2;

Use base metal: A45C.

RolClad and control group 2 were welded to the surface of the base material for observation. The experimental results are shown in Fig. 1A and Fig. 1B. RolClad and control group 2 were tested and observed under the conditions of humidity 80% and temperature 30 °C. Figure 1A shows The RolClad of the present invention and FIG. 1B are the control group 2, and it can be found that the control group 2 apparently produces a plurality of rust spots, and in contrast, the RolClad does not have any rust.

Example 2

Anti-temper softening test

The experimental conditions for the anti-temper softening test are as follows:

Test reaction temperature: 0 ° C, 200 ° C, 300 ° C, 400 ° C, 500 ° C, 550 ° C, 600 ° C, 700 ° C and 800 ° C;

Reaction time: 20 days;

Use welding consumables: RolClad;

Molybdenum content of the consumables: 0%, 0.5%, 1.5%, 2.0% and 3.0%;

Measuring hardness instrument: Victoria hardness machine.

The RolClad of the present invention is subjected to an anti-temper softening test, and the content of molybdenum of RolClad is changed for testing. The experimental results are shown in FIG. 2, and the molybdenum contents of RolClad are 0%, 0.5%, 1.5%, 2.0%, and 3.0%, respectively. When the tempering temperature is between 500 ° C and 550 ° C, it can be observed that when the content of molybdenum is increased to 1.5%, its ability to resist temper softening is more remarkable, and its Vickers hardness can reach about 310 Hv, and when the molybdenum of RolClad The higher the content (2.0% and 3.0%), the higher the hardness and the resistance to temper softening, the Vickers hardness can reach up to about 370Hv; and the non-molybdenum RolClad has very poor temper softening resistance. .

Example 3

For the test of the resistance to hot cracking of high carbon base materials, when the carbon content of the base material is 0.3% by weight or less, it is called low carbon base material; when the weight percentage of carbon content of the base material is between 0.3% and 0.6% It is called a medium carbon base material; when the carbon content of the base material is between 0.6% and 2.0% by weight, it is called a high carbon base material.

Taking a high-carbon base material with a carbon content of 0.6%, three kinds of welding consumables made of different metal element percentages were designed for welding test. The metal composition ratio is shown in Table 3:

The experimental conditions for resistance to solder thermal cracking are as follows:

Welding parameters: 400A/30V/ESO30mm/40cpm;

Welding preheating temperature: 350 ° C;

Use welding consumables: control group 3, control group 4 and control group 5 as listed in Table 3 above;

The base metal was used: S60C (high carbon base material with a carbon content of 0.6%).

The control group 3 was welded to a high-carbon base material having a carbon content of 0.6%. The results are as shown in FIG. 3A and FIG. 3B. The weld bead is enlarged and observed, and hot cracks having uniform directivity are found on the weld bead; Group 4 was welded to a high carbon base material having a carbon content of 0.6%. As a result, as shown in FIG. 4A and FIG. 4B, the weld bead was enlarged and observed, and hot cracks were generated on the weld bead, and the thermal crack was compared with FIG. 3B. Less consistent directionality; the control group 5 was welded with a high carbon base material having a carbon content of 0.6%. As a result, as shown in FIG. 5A and FIG. 5B, the weld bead was enlarged and observed, and no hot crack occurred on the weld bead.

It can be inferred from the above results that the higher the content of molybdenum in the welding consumable, the less prone to hot cracking on the weld bead, and the absence of hot cracking helps to prolong the service life of the high carbon base metal, and indicates that the consumable is high carbon mother The material has a good tolerance, so that the high carbon base material can be repaired and the cost is reduced.

Further, the RolClad of the present invention was subjected to a soldering test with the control group 1 to test a high carbon base material having a carbon content of 1.2%, and the metal component ratio of the RolClad to the control group 1 is as shown in Table 4:

The experimental conditions for resistance to solder thermal cracking are as follows:

Welding parameters: 400A/30V/ESO30mm/40cpm;

Welding preheating temperature: 350 ° C;

The welding consumables were used: RolClad and the control group 1 shown in Table 4 above; and the base material: bearing steel SUJ2 (high carbon base material having a carbon content of 1.2%).

The results of the control group 1 welded to the high carbon base material having a carbon content of 1.2% are shown in Fig. 6A and Fig. 6B. In Fig. 6A, a hot cracked structure can be clearly seen, and the weld bead is enlarged and observed, and the weld bead is generated in the center. A hot cracked structure and hot cracks with uniform directionality were observed. The weld metallographic structure of the control group 1 showed smooth columnar crystals. The stress generated by this type of structure was large and the cracks were easy to follow. The grain boundary of the columnar crystal structure is cracked; the result of welding RolClad to a high carbon base material having a carbon content of 1.2% is as shown in FIG. 7A and FIG. 7B, and the weld bead is enlarged and observed, and no hot cracked structure is generated, so It is confirmed that the RolClad of the present invention has high tolerance to high-carbon base materials and is not prone to thermal cracking. It is found that the weld bead structure of RolClad exhibits dendritic structure by welding metallographic structure, and the stress generated by this type of structure is small. And when a small crack is generated, the dendrite grain boundary is curved or discontinuous to hinder the crack growth. When the molybdenum content of RolClad is more than 1.4%, the grain solidification of the bead can be refined and the dendritic structure is generated. Is lowering The main mechanism of welding hot cracking.

The RolClad of the present invention was tested for resistance to solder thermal cracking and the content of molybdenum of RolClad was changed.

The experimental conditions for resistance to solder thermal cracking are as follows:

Welding parameters: 400A/30V/ESO30mm/40cpm;

Welding preheating temperature: 350 ° C;

Use welding consumables: RolClad;

Molybdenum content of welding consumables: 0%, 0.15%, 0.35%, 0.55%, 0.57%, 0.6%, 0.65%, 0.67%, 0.7%, 1%, 1.2%, 1.3%, 1.4%, 1.45%, 1.5%, 1.52%, 1.75%, 2%, 2.1%, 2.25%, 2.34%, 2.65%, 2.7%, 3.1%;

Use base metal: bearing steel SUJ2.

The experimental results are shown in Fig. 8. The higher the molybdenum content of RolClad, when the molybdenum content exceeds about 1.4%, the ratio of weld thermal cracking approaches zero, indicating that the phenomenon of weld hot cracking hardly occurs.

In a preferred embodiment of the RolClad of the present invention, the percentage of each metal element is as shown in Table 4:

The application characteristics of RolClad, control group 1 and control group 2 were compared, and the results are shown in Table 5:

According to the foregoing experiment, the RolClad of the present invention has good physical properties, can withstand the dilution of the high-carbon base material, and does not cause welding hot cracking, and can be applied to the hard surface repair of the high-carbon base material.

The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. The present invention has been described above by way of a preferred embodiment, but is not intended to limit the invention, and any skilled person skilled in the art. The equivalent embodiments of the above-disclosed technical contents may be modified or modified to equivalent variations, without departing from the technical scope of the present invention, and in accordance with the present invention, without departing from the scope of the present invention. It is still within the scope of the technical solution of the present invention to make any simple modifications, equivalent changes and modifications to the above embodiments.

1A is a comparison of the results of the pitting resistance test of the control group 2 of FIG. 1B with the present invention.

Figure 2 is a graph showing the results of an anti-temper softening test in which the molybdenum content of the present invention is adjusted.

3A and 3B are weld bead diagrams of the control group 3 welded to a high carbon base material having a carbon content of 0.6%. FIG. 3B is an enlarged view of FIG. 3A.

4A and 4B are weld bead diagrams of the control group 4 welded to a high carbon base material having a carbon content of 0.6%. 4B is an enlarged view of FIG. 4A.

5A and 5B are weld bead diagrams of the control group 5 welded to a high carbon base material having a carbon content of 0.6%. FIG. 5B is an enlarged view of FIG. 5A.

6A and 6B are weld bead diagrams of the control group 1 welded to a high carbon base material having a carbon content of 1.2%. 6B is an enlarged view of FIG. 6A.

7A and 7B are weld bead diagrams of a high carbon base material welded to a carbon content of 1.2% according to the present invention.

Figure 8 is a graph showing the results of testing the thermal cracking sensitivity of the present invention by adjusting its molybdenum content.

Claims (9)

A hard surface repairing welding material consisting mainly of carbon, molybdenum and iron, wherein the carbon element accounts for 0.02 to 0.10% by weight of the whole welding consumable; and the molybdenum element accounts for 1.4% by weight of the whole welding consumable. Between 3%; the hard surface repairing welding material further comprising manganese element, which accounts for 1.0 to 3.0% by weight of the whole welding consumable; and cerium element, which accounts for the weight percentage of the whole welding consumable Between 0.3 and 1.0%; and chromium element, which accounts for between 0.6 and 3.5% by weight of the overall consumable; and sulfur element, which accounts for less than 0.03% by weight of the overall consumable; and phosphorus, which accounts for The weight percentage of the overall welding consumable is 0.03% or less; the hard surface repairing welding material has a dendritic bead structure having a grain boundary which is curved or discontinuous to hinder the growth of cracks. The hard surface repair welding material according to claim 1, wherein the carbon element accounts for 0.03% by weight of the whole welding material; the manganese element accounts for 2.1% by weight of the whole welding material; the bismuth element accounts for the whole welding material. The weight percentage is 0.6%; the chromium element accounts for 0.7% by weight of the whole welding consumable; the molybdenum element accounts for 3% by weight of the whole welding consumable; the sulfur element accounts for 0.03% or less of the whole welding consumable; and the phosphorus element accounts for The weight percentage of the overall welding consumable is 0.03% or less. The hard surface repairing consumable according to claim 1 or 2, which can be applied to a high carbon base material selected from the group consisting of bearing steels SUJ2, SUJ3, SUJ4, and SUJ5. A hard surface repair welding material as described in claim 3, which is resistant to holes The eclipse system is between 12.09 and 61.21. The hard surface repairing consumable according to claim 3, wherein the temperature is heated to about 550 ° C, and the Vickers hardness is between 310 Hv and 370 Hv. The hard surface repairing consumable according to claim 4, wherein the temperature is heated to about 550 ° C, and the Vickers hardness is between 310 Hv and 370 Hv. A hard surface repairing welding material consisting of carbon, molybdenum, manganese, strontium, chromium, sulfur, phosphorus and iron, wherein the carbon element accounts for 0.02 to 0.10% by weight of the whole welding consumable; The weight percentage of the overall welding consumable is between 1.4 and 3%; the manganese element accounts for 1.0 to 3.0% by weight of the whole welding consumable; the niobium element accounts for 0.3 to 1.0% by weight of the whole welding consumable; the chromium element The weight percentage of the whole welding consumable is 0.6 to 3.5%, the sulfur element accounts for 0.03% or less of the total weight of the welding consumable; and the phosphorus element accounts for 0.03% or less of the total weight of the welding consumable; the hard surface repairing consumable has A dendritic bead structure having a grain boundary that is curved or discontinuous to hinder the growth of cracks. A method for repairing a hard surface welding material, comprising: providing a high carbon base material having a carbon content of 0.6% by weight or more, and welding using the hard surface repair welding material of any one of claims 1 to 7; A hard surface repaired base material is obtained. For the method of repairing the hard surface welding material according to Item 8 of the patent application, the welding parameter is current 400A/voltage 30V/welding height ESO30mm/welding speed 40cpm; and the welding preheating temperature is 350°C.