Laser-manufactured maraging stainless steel material for hot-rolled strip steel coiling front side guide plate and preparation process thereof
Technical Field
The invention belongs to the technical field of C23C24/10(2006.01) I in the International patent Classification, and relates to a stainless steel material for a side guide plate, in particular to a laser-manufactured maraging stainless steel material for a hot-rolled strip steel coiling front side guide plate and a preparation process thereof.
Background
With the rapid development of the fields of ocean development, petrochemical industry and steel industry, the requirements on high-strength stainless steel which has high strength, high toughness, high wear resistance, easy processing, forming and welding and better comprehensive performance are increased. The high-strength stainless steel generally includes precipitation hardening stainless steel, maraging stainless steel, and ferritic stainless steel. Among them, precipitation hardening stainless steel has poor toughness and cold forming workability, while ferritic stainless steel has low strength, so that the maraging stainless steel has high strength and high toughness, which is an important research object.
In the steel production line, the coiling front side guide plate is important equipment on the hot rolling production line, has an effect on the core of the final coil type of the steel coil, and can be one of the most important equipment influencing the qualification rate of finished products. In the actual production process, the service material used by the side guide plate is generally a common wear-resistant surfacing material, the strength and the toughness of the material are poor, the surfacing material can crack or even fall off due to the violent impact in the strip steel coiling process in the long-time service process, the condition can cause serious coiling process accidents, and waste and defective products caused by coiling defects further cause unnecessary cost waste. Therefore, the selection of a proper material for the guide ruler lining plate improves the overall high strength and high toughness of the service material, improves the quality of the coiled material, avoids the falling of the blocks and the falling off, greatly prolongs the service life of the side guide plate on the premise of ensuring the coiled steel strip shape, and is a problem to be solved at present.
The speed of the strip steel contacted by the side guide plate in the actual working process can reach 17m/s, and along with the whole-process contact of high pressure and the side part of the strip steel, a deep abrasion groove is formed on the side edge of the strip steel, even the dynamic balance of the strip steel operation is directly damaged, so that mechanical vibration is caused, the steel coiling quality is influenced, and even coiling accidents are caused. The material of the guide shoe must therefore have the following performance characteristics: high strength and toughness and good wear resistance.
The laser cladding technology is an advanced manufacturing technology, alloy powder with specific performance characteristics and a base material are simultaneously melted by utilizing the characteristic of extremely high laser beam gathering energy to form a novel composite material, and meanwhile, a compact cladding layer which is metallurgically combined with the base body can be further obtained by refining crystal grain structures due to the fact that rapid cooling solidification can be realized after laser cladding, so that a specific strengthening purpose is achieved. At present, no corresponding material exists in the field of laser cladding aiming at the material.
Disclosure of Invention
In order to solve the problem that a surfacing layer is easy to fall off and fall off in the prior art, the invention aims to provide the maraging stainless steel material which has high strength, high toughness and wear resistance and is used for laser manufacturing of the coiled front side guide plate of the hot-rolled strip steel and the preparation process thereof. The invention adopts a laser cladding method to manufacture the hot-rolled strip steel side guide plate. The maraging stainless steel material is mainly characterized in that the carbon content in the material is reduced, the chromium content of a certain component is guaranteed, the contents of nickel, cobalt, molybdenum, manganese and the like are increased, the austenite is enlarged, more martensite is guaranteed to be formed, and meanwhile, the integral performance is strengthened by means of dispersion precipitation of intermetallic compounds. The material has some unique properties: the material has high strength and toughness, good formability, almost no deformation during aging, and compact and flawless structure through proper laser cladding process, which shows that the material has good welding performance and is suitable for wide popularization and application. And because the toughness of the matrix material is better, the crack tendency is extremely small under the proper laser cladding process.
In order to achieve the purpose, the invention adopts the following technical scheme.
A laser-produced maraging stainless steel alloy powder material for hot rolled strip curl front guides, said alloy powder having a composition comprising Cr: 2-15%, Ni: 2-5%, Co: 2-8%, Mn: 0.3-0.9%, Cu: 0.1-1.5%, Mo: 1-8%, B: 0.2-0.6%, Fe: and (4) the balance.
The maraging stainless steel alloy powder material for the hot-rolled strip steel curling front side guide plate manufactured by the laser is prepared by the procedures of vacuum melting, vacuum gas atomization, screening and the like, and the granularity is-100 to +270 meshes.
A preparation method of a laser-manufactured maraging stainless steel alloy powder material for a hot-rolled strip steel curling front side guide plate is suitable for an all-solid-state solid laser, and the powder material is applied with the cladding process parameters as follows: power: 700-1500W, spot diameter: 1.8-3.8mm, scanning speed: 12-55mm/s, powder placement thickness: 1.2-1.8 mm.
Compared with the prior art, the invention has the following beneficial effects.
The invention develops a high-strength high-toughness wear-resistant laser composite maraging stainless steel material by researching and analyzing a wear mechanism system of a side guide plate. Different from the traditional wear-resistant material, the invention develops a novel high-strength high-toughness maraging stainless steel on the basis of solving the traditional wear-resistant problem, the maraging stainless steel takes ultra-low carbon iron-nickel martensite as a matrix, intermetallic compounds can be generated during aging so as to play a role of precipitation hardening, and the maraging stainless steel has certain toughness due to the ultra-low carbon, so the maraging stainless steel is more suitable for the service environment of side guide plates, has high strength and does not have the risk of falling off and dropping blocks.
The invention utilizes the mode of reducing the carbon content and increasing the precipitation strengthening of the intermetallic compound, mainly through the ultra-low carbon content and selecting proper element proportion, promotes the expansion of the austenite area and stably exists, forms the intermetallic compound by different component element proportions and precipitates and disperses in the matrix through certain heat treatment process aging, so that the alloy powder obtains more excellent comprehensive performance, thereby realizing that the alloy has higher hardness, higher strength and good toughness, realizing the structure with good crack-free processing performance through a laser cladding means, forming a compact metallurgical bonding layer with the base material of the side guide plate, having reliable toughness and meeting the use requirement of the laser cladding side guide plate.
The cobalt with a proper proportion can not only reduce the solid solubility of molybdenum in martensite, but also promote the precipitation of intermetallic compounds of molybdenum, thereby directly improving the strengthening effect and obtaining an alloy structure with good comprehensive performance. If the proportion of cobalt and molybdenum elements is low and the precipitation of intermetallic compounds of molybdenum is high, the cracking risk of alloy structures is increased, and the products have the risks of cracking, falling blocks and the like under severe working conditions such as violent impact and the like; if the proportion of cobalt and molybdenum elements is higher, the precipitation of intermetallic compounds of molybdenum is less, and the strength of the alloy structure is insufficient. Therefore, the cobalt and molybdenum synergistic effect has a positive effect on the alloy structure performance of the product of the laser cladding side guide plate.
By using a laser cladding means, the wear-resistant effect which can be achieved only by 6mm before can be achieved by the thickness of 1.2-1.8mm, and mainly due to the aging precipitation strengthening result of the second phase particles, namely the intermetallic compound, the wear-resistant performance of unit thickness is improved, the coiling precision is guaranteed, and the safety and stability of product use are guaranteed.
Detailed Description
The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.
A laser-produced maraging stainless steel alloy powder material for hot rolled strip curl front guides, said alloy powder having a composition comprising Cr: 2-15%, Ni: 2-5%, Co: 2-8%, Mn: 0.3-0.9%, Cu: 0.1-1.5%, Mo: 1-8%, B: 0.2-0.6%, Fe: and (4) the balance.
The maraging stainless steel alloy powder material for the hot-rolled strip steel curling front side guide plate manufactured by the laser is prepared by the procedures of vacuum melting, vacuum gas atomization, screening and the like, and the granularity is-100 to +270 meshes.
A preparation method of a laser-manufactured maraging stainless steel alloy powder material for a hot-rolled strip steel curling front side guide plate is suitable for an all-solid-state solid laser, and the powder material is applied with the cladding process parameters as follows: power: 700-1500W, spot diameter: 1.8-3.8mm, scanning speed: 12-55mm/s, powder placement thickness: 1.2-1.8 mm.
The equipment used for the friction and wear test, in particular due to the specific synergy of cobalt and molybdenum, in the proportions of the two components is a "universal friction and wear tester". The specific test conditions were as follows:
(1) test equipment: universal friction wear testing machine;
(2) the ratio of cobalt and molybdenum components is as follows: 1 (comparison group), 1-2.5, 2.5-4, 4-5.5, 5.5-7;
(3) grinding materials: silicon nitride;
(4) friction conditions: dry friction;
(5) test temperature: 120 ℃;
(6) friction loading force: 150 KN;
(7) revolution number: 500 r/min;
(8) test time: and (3) 30 min.
The percentage content of each element is adjusted, austenite forming elements such as cobalt, molybdenum and the like are added into the maraging stainless steel at the same time, the appropriate proportion is adjusted, and the test results are shown in the following table after the transverse comparison test of different proportion combinations of a universal friction wear tester:
table 1 universal friction and wear test combined wear data for different cobalt and molybdenum ratios.
Injecting: the higher the wear resistance value shows, the higher the wear resistance of the material is demonstrated.
According to the invention, data are obtained through the test, and the data are converted into the numerical value of the wear resistance through statistical wear weight loss data, so that the wear resistance of the designed materials with different cobalt-molybdenum proportions in the transverse comparison process can be judged. Finally, the range of the synergistic action ratio of cobalt and molybdenum is 4-5.5, so that the optimal wear-resisting property can be obtained.
Example 1.
When the side guide plate of a hot rolling production line of a certain steel mill in Hebei is used, the falling and the falling of the side guide plate material caused by the violent impact of the edge of strip steel can occur in 24 hours on average, and the whole roll of strip steel can be directly turned into waste products in serious cases. Causing serious cost waste.
After the maraging stainless steel alloy powder material applied by the invention is used for laser cladding manufacturing, the laser cladding parameters are as follows: power: 1350W, spot diameter: 3.5mm, scanning speed: 28mm/s, powder placement thickness: 1.5 mm. The invention provides a method for cladding by using 200-mesh maraging stainless steel alloy powder for laser manufacturing of a hot-rolled strip steel curling front side guide plate, which comprises the following components in percentage by mass: 12.5 percent of Cr; 3.7 percent of Ni; 6.2 percent of Co; 0.4 percent of Mn; 0.3 percent of Cu; 1.2 percent of Mo; 0.3 percent of B; the balance of Fe.
The size and the precision required by the original design are recovered after the design by a proper cladding process. The machine is in service under the actual working condition, and the cracking and the chipping do not occur after the service life reaches 196 hours. Namely, the material is proved to completely meet the design specification. The specific characterization is shown in table 1. Service time represents the strength and wear resistance of the strip steel product, whether the strip falls or not represents the obdurability and welding density, whether the sticky steel appears or not represents the uniform distribution of intermetallic precipitates, and further represents the properties of good precipitation and uniform distribution of tissue aging, and groove edge description represents that the product has excellent toughness, smooth transition shows that the material has compact tissue and good welding performance, and the edge of the strip steel product is not damaged in the groove state, so that the strip steel product is suitable for wide popularization and use.
Table 2. original side guides and laser cladding side guides.
Example 2.
In the use process of the guide ruler lining plate of a certain steel mill in Shandong, the condition that the guide ruler lining plate falls off and falls off after being used for 32 hours on average already causes the downshifting treatment of 22 coiled steel, and the working efficiency of a production line is seriously influenced by the stopping mode when the condition is treated.
The material is used for laser cladding. The laser cladding parameters are power: 1500W, spot diameter: 1.8mm, scanning speed: 33mm/s, powder placement thickness: 1.5 mm. Cladding by using the powder with the granularity of 230 meshes, and the components are as follows: 13.5 percent of Cr; 3.9 percent of Ni; 5.5 percent of Co; 0.6 percent of Mn; 1.3 percent of Cu; 1.5 percent of Mo; 0.3 percent of B; the balance of Fe.
The original size and precision are recovered through proper laser cladding design, and the design requirement is met. And (3) assembling the material on a hot rolling line for online testing, taking the material out of the hot rolling line for 260 hours, obtaining a test result until the material is worn out of the hot rolling line, wherein the block falling condition does not occur, and the surface condition is smooth and complete, which is enough to show that the service performance of the material is far beyond the design index. Specific comparative characterizations are given in table 2 below. Service time represents the strength and wear resistance of the strip steel product, whether the strip falls or not represents the obdurability and welding density, whether the sticky steel appears or not represents the uniform distribution of intermetallic precipitates, and further represents the properties of good precipitation and uniform distribution of tissue aging, and groove edge description represents that the product has excellent toughness, smooth transition shows that the material has compact tissue and good welding performance, and the edge of the strip steel product is not damaged in the groove state, so that the strip steel product is suitable for wide popularization and use.
Table 3. comparison of original side guides and laser clad side guides.