Roller laser cladding alloy material with improved toughness
Technical Field
The invention belongs to the field of metal materials, and particularly relates to a roller laser cladding alloy material with improved toughness.
Background
The roller is one of important consumables in the industrial rolling process, and the variety and the manufacturing process of the roller are continuously developed along with the improvement of metallurgical technology and the evolution of steel rolling equipment. The low-strength gray cast iron roller is used for rolling soft nonferrous metal in the middle century. The uk in the middle of the 18 th century mastered the technology for producing chilled cast iron rolls for rolling steel plates. The progress of the European steelmaking technology in the second half of the 19 th century requires rolling of ingots of larger tonnage, neither gray cast iron nor chilled cast iron rolls have met the required strength. The common cast steel roller with the carbon content of 0.4 to 0.6 percent is correspondingly produced. The appearance of heavy forging equipment further improves the toughness of the forging roller with the composition. The use of alloying elements and the introduction of heat treatments in the early 20 th century significantly improved the wear and toughness of cast and wrought steel hot and cold rolls. The surface quality of the rolled material is improved after molybdenum is added into a cast iron roller for hot rolling the plate strip. The core strength of the casting roller is obviously improved by the composite pouring of the flushing method.
In order to meet the production requirements, higher requirements are put on the strength, hardness, wear resistance, high temperature resistance, toughness and the like of the roller.
The laser cladding technology is a new surface modification technology which is developed along with the development of a high-power laser in the 70 th century, and is a surface strengthening method which is used for rapidly heating and melting alloy powder or ceramic powder and the surface of a matrix under the action of a laser beam, forming a surface coating which has extremely low dilution rate and is metallurgically combined with the matrix material by self-excitation cooling after the laser beam is removed, and further remarkably improving the wear resistance, toughness, corrosion resistance, heat resistance, oxidation resistance, electrical properties and the like of the surface of the matrix.
At present, more and more laser cladding technologies are applied to the roller to repair the damaged roller and prolong the service life of the roller.
Disclosure of Invention
The invention aims to provide a roller laser cladding alloy material with improved toughness, which reduces roller fracture and prolongs the service life.
The specific technical scheme of the invention is as follows:
the invention provides a roller laser cladding alloy material for improving toughness, which comprises the following raw materials in percentage by weight:
preferably, the roller laser cladding alloy material with improved toughness comprises the following raw materials in percentage by weight:
further, the grain diameter of the alloy material laser-clad by the roller is controlled to be 20-50 μm.
The roller laser cladding alloy material for improving the toughness is coated on the surface of the roller, and the method specifically comprises the following steps:
1) roller pretreatment: removing grease, cracks and corrosion spots on the surface of the roller; then, the roller is heated to 540-.
2) Laser cladding;
3) and (5) preserving heat and slowly cooling.
The step 2) is specifically as follows: the power is 1800 plus 2500W, the lapping rate is 40-45%, the diameter of the light spot is 3-4mm, the scanning speed is 500 plus 800mm/min, and the powder feeding speed is 20-28 g/min.
The step 3) is specifically as follows: cooling to 300-320 ℃ at the speed of 20-25 ℃/min, preserving the heat for 1-2.5 hours, and then slowly cooling to room temperature in the air.
Further, the thickness of the cladding layer is 3-8 mm.
According to the invention, C, N, Ti, B, Si and Nb are added into the roller laser cladding alloy material, and compounds Ni-B, Ni-N, BN and the like are formed in the alloy layer through laser cladding, so that the toughness is improved. And the two elements of Nb and Ti are adopted, the dosage ratio is controlled, the elements are favorably stabilized, the toughness is further improved, the fracture is reduced, and the service life is prolonged. Moreover, the added C, Cr and Al are equal to Ni to form compounds in the alloy layer, which is beneficial to improving the wear resistance.
The alloy material formula is matched, the cladding process is designed, pretreatment before cladding is firstly carried out, the heating speed of the roller is controlled, then cladding is carried out, the uniformity of a cladding layer is ensured, and the cladding layer is better fused with the surface of the roller. And then, controlling the heat preservation slow cooling speed after cladding, preventing the cladding layer from suddenly shrinking to generate cracks at a low temperature, and enabling the cladding layer to be better fused with the surface of the roller.
Compared with the prior art, the invention improves the wear resistance and toughness, reduces the conditions of fracture, cracking and the like and prolongs the service life of the roller by controlling the formula of the alloy material and matching with the cladding process.
Detailed Description
Example 1
The roller laser cladding alloy material for improving the toughness comprises the following raw materials in percentage by weight:
the roller laser cladding alloy material for improving the toughness is coated on the surface of the roller, and the method specifically comprises the following steps:
1) roller pretreatment: removing grease, cracks and corrosion spots on the surface of the roller; then, the roller is heated to 545 ℃ according to the heating rate of 35 ℃/h, and the temperature is kept for 3 h.
2) Laser cladding, parameters: the power is 2000W, the lapping rate is 40%, the diameter of a light spot is 3mm, the scanning speed is 600mm/min, and the powder feeding speed is 20 g/min.
3) And (4) carrying out heat preservation and slow cooling, cooling to 320 ℃ at the speed of 20 ℃/min, carrying out heat preservation for 1.5 hours, and then carrying out slow cooling to room temperature in the air.
Example 2
The roller laser cladding alloy material for improving the toughness comprises the following raw materials in percentage by weight:
the roller laser cladding alloy material for improving the toughness is coated on the surface of the roller, and the method specifically comprises the following steps:
1) roller pretreatment: removing grease, cracks and corrosion spots on the surface of the roller; then, the roller is heated to 550 ℃ according to the heating rate of 45 ℃/h, and the temperature is kept for 2 h.
2) Laser cladding, parameters: the power is 2500W, the lapping rate is 45%, the diameter of a light spot is 4mm, the scanning speed is 700mm/min, and the powder feeding speed is 25 g/min.
3) And (4) preserving heat and slowly cooling, namely cooling to 305 ℃ at the speed of 25 ℃/min, preserving heat for 1-21.5 hours, and then slowly cooling to room temperature in the air.
Comparative example 1
The roller laser cladding alloy material for improving the toughness comprises the following raw materials in percentage by weight:
the roller surface is coated with the laser cladding alloy material for improving the toughness, and the same as the embodiment 1 is carried out.
Comparative example 2
The roller laser cladding alloy material for improving the toughness comprises the following raw materials in percentage by weight:
the use method of the roller laser cladding alloy material is characterized in that the pretreatment and slow cooling are not carried out, the laser cladding is directly carried out, and the specific parameters are the same as those in the embodiment 2.
Comparative example 3
Rolls without any treatment.
The materials of the rolls treated by the embodiment 1, the embodiment 2, the comparative example 1, the comparative example 2 and the comparative example 3 are the same, after treatment, 100 rolls are respectively taken, after the work with the same working strength is carried out, the toughness, the wear resistance, the cladding layer surface quality and the fracture condition after the same working strength are respectively detected and recorded, and the results are shown in the following table 1:
TABLE 1 test results
Compared with the prior art, the laser cladding alloy material provided by the invention has excellent hardness, wear resistance, corrosion resistance and crack resistance.