JP2002235113A - Method for producing stock for loom member made of high strength steel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a loom member made of a high strength steel which has increased fiber wear resistance by dispersing hard Ti carbides and Nb carbides into a matrix, and has improved corrosion resistance and toughness by undergoing heat treatment at proper quenching and tempering temperatures. SOLUTION: A steel having a composition containing, by mass, 10 to 18% Cr and 0.05 to 0.5% C, and further containing Ti and/or Nb by 0.05 to 1% in Ti alone and 0.05 to 1% in Nb alone or Ti+Nb by 0.05 to 1% in total, and the balance substantially Fe is subjected to heat treatment at a quenching temperature of T±50 deg.C to T obtained by the following formulae (1) and (2) and at a tempering temperature of 150 to 500 deg.C to form the structure of the steel into a matrensitic phase. Further, the carbides of Ti and/or Nb are dispersedly precipitated into the matrix of the steel in an amount of >=0.1%: T=280×k*+1200 (1), and k*=log C%-0.16(Nb%+Ti%)} (2).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loom member such as a flat heald, a dropper, a reed, a deformed reed, a reed or the like which is easily worn by contact with a fiber, and is excellent in corrosion resistance, toughness and fiber abrasion resistance. The present invention relates to a method for producing a material for a high-strength steel loom member excellent in quality.

[0002]

2. Description of the Related Art Stainless steel SUS42 is used for loom members such as flat healds, droppers, reed feathers, deformed reeds, and reeds.
A structure reinforcing material obtained by quenching 0J2 is used. The weaving environment of this type of loom member has become severe with the increase in speed and the like in order to improve the quality of fibers used in the woven fabric and to improve production efficiency. As a result, the life of the parts is shortened, and complicated replacement of the repair parts is inevitable.
Further, depending on the use environment, there is a problem that the loom member is corroded and the woven fabric is contaminated.

[0003]

DISCLOSURE OF THE INVENTION The present invention has been devised to solve such a problem, and the resistance to fiber abrasion is improved by dispersing hard Ti carbide or Nb carbide in a matrix. Abrasion and proper quenching
An object of the present invention is to provide a high-strength steel loom member having excellent corrosion resistance, toughness, and fiber wear resistance that is used for a long period of time by using a high corrosion-resistant material built at a tempering temperature.

[0004]

SUMMARY OF THE INVENTION The method of the present invention for producing a material for a high-strength steel loom member excellent in corrosion resistance, toughness and fiber abrasion resistance is intended to achieve its object.
8% by mass, C: 0.05 to 0.5% by mass, further containing Ti and / or Nb, Ti:
1% by mass, Nb: 0.05 to 1% by mass alone or Ti
+ Nb: A steel containing 0.05 to 1% by mass in total and the balance being substantially composed of Fe, having a quenching temperature of T ± 50 with respect to T determined by the following formulas (1) and (2). C. and a tempering temperature of 150 to 500 [deg.] C., heat-treating the steel to form a martensitic phase and dispersing and precipitating 0.1 mass% or more of carbides of Ti and / or Nb in a steel matrix. It is assumed that. Here, T = 280 × k ^* + 1200 {(1) k ^* = log {C% −0.16 (Nb% + Ti%)} (2)

[0005]

The present inventors ordered a large number of worn and damaged loom members and actually used fibers, and investigated the worn and damaged portions and fibers from a microscopic viewpoint. As a result, in most of the worn members, flaws such as fine linear grinding were observed in the worn portion. Further, adhesion of hard particles such as alumina and silicon carbide was detected on the used fibers. From the scratches and the attachment of the hard particles as if they were ground, it was found that the wear phenomenon at this time was abrasion mediated by the hard particles. In the present specification, wear in which hard particles are present on the contact surface between the fiber and the loom member and the contact surface of the loom member is rubbed or ground by the hard particles or the like in a vibration or sliding process is referred to as abrasive wear. Abrasive wear is the most severe wear among various wear phenomena, and it is desired to develop a material that can withstand this wear.

[0006] Conventional steel loom members are resistant to abrasive wear because hard particles such as alumina and silicon carbide are harder than the hardness obtained by strengthening the structure and hardening the steel. Did not. Therefore, the present inventors focused on carbides having the same hardness as alumina and silicon carbide, dispersed hard carbides in a steel matrix, and studied abrasion resistance against abrasive wear. As a result, it has been found that dispersing and precipitating Ti carbide or Nb carbide alone or in combination has an effect of suppressing abrasive wear due to alumina or silicon carbide, and has excellent wear resistance for a loom member for a loom member. Wear steel was developed. The present inventors have further studied the improvement of corrosion resistance and toughness. As a result, they have found that the corrosion resistance and toughness are improved in relation to the added elements and the amounts thereof and the quenching and tempering temperatures.

Here, various evaluation and measurement methods used for evaluating the characteristics of the steel material obtained by the method of the present invention will be described.
Let me explain. [Measurement of Carbide Precipitation Amount] A sample in which the amount of carbide was controlled by solid solution / precipitation treatment of carbide was immersed in an alcohol iodide solution, and ultrasonic waves were applied to dissolve the steel. It was determined from the amount of residue. The form of the carbide was determined by X-ray analysis of the residue, and the amount of each metal element was determined by a wet analysis and a gas analyzer.

[Evaluation of corrosion resistance]
A salt spray test according to 2371 was carried out for 72 hours, and the presence or absence of rust after the test was evaluated. [Evaluation of toughness] Evaluation of toughness after quenching and tempering
Evaluation was made based on the presence or absence of breakage at the bent part by close contact or bending, by the push bending method of Z2248.

[Evaluation of abrasion resistance] In the test, a chemical fiber of a woven fabric (TFD 75 / 36F outer diameter: about 120 μm) was passed through the mail hole of the flood heald, and the slidable contact was performed to measure the abrasion depth of the contact portion. The test conditions were as follows: fiber tension: about 50 g
And the test rotation speed: 80 rpm (sliding speed: 0.1 m
/ S), test time: 10 hours. The abrasion resistance of the mail portion of the test specimen floodheld was determined by calculating the amount of wear in the portion in contact with the fiber and using the abrasion depth of SUS420J2 as a reference, based on the following equation (3).
(%). The smaller the wear resistance index M, the better the wear resistance. Abrasion resistance index M (%) = Di ÷ Do × 100 ‥‥‥ (3) where Do is the wear depth of SUS420J2, and Di is the wear depth of the steel to be evaluated.

Next, the contents of the method of the present invention will be specifically described. The steel material targeted in the present invention contains 10 to 18% by mass of Cr in order to impart corrosion resistance. When the Cr content is less than 8% by mass, the anticorrosion effect due to the addition of Cr is reduced. Corrosion resistance improves as Cr is added to 10% by mass or more, but hot workability decreases when it exceeds 18% by mass,
This is a manufacturing problem. The upper limit of Cr is set to 18% by mass in consideration of the corrosive environment in which the material of the present invention is used and to reduce the cost of the material.

Ti: and / or Nb: Ti: 0.05 to 1% by mass alone, Nb: 0.05 to 1% by mass alone such that the total amount of carbide precipitation is 0.1% by mass or more.
Or Ti + Nb: added at a ratio of 0.05 to 1% by mass in total amount. The total carbide precipitation of 0.1% by mass or more
As described in Examples below, it is a critical value found from an investigation of the effect of precipitates on abrasion resistance. 0.
By securing a total precipitation amount of 1% by mass or more, much superior wear resistance can be obtained as compared with a steel material having no carbide. Ti: 0.05% by mass or more, Nb: 0.05% by mass
When the above or Ti + Nb is set to 0.05% by mass or more, the total amount of carbides dispersed and precipitated in the matrix becomes 0.1% by mass or more. However, the Ti and Nb components have a lower limit of the Ti content of 1.0% by mass and a lower Nb content because of lowering of the fluidity during melting, lowering of the toughness due to the formation of intermetallic compounds, and higher material costs. 1% by mass, T
The upper limit of the total content of i + Nb was set to 1% by mass.

In order to precipitate carbides of 0.1% by mass or more, it is necessary to contain C in an amount of 0.05% by mass or more. C is not only consumed in the formation of carbides, but is also an effective component for strengthening the structure. However, the addition of a large amount of C exceeding 0.5% by mass causes a large amount of precipitation of eutectic chromium carbides, The upper limit of the C content is set to 0.5% by mass in order to cause a decrease in material quality and a decrease in hot workability. In the steel material targeted in the present invention, Zr, V, W, etc., which are hard carbide-forming elements for improving abrasion resistance, are partially substituted with Ti, Nb or added in combination with Ti and / or N
It can be added up to 1% by mass in total with b.

[0013] Further, the steel materials targeted by the present invention include:
Ni, Mo, Cu and the like can be contained as other alloy components. For example, in order to secure a martensite phase after quenching and further improve toughness, 0.1 to 4% by mass of N
i, Mo of 0.1 to 3% by mass for improvement of corrosion resistance, 0.2 to 3% by mass of Mo for improvement of corrosion resistance, stress corrosion cracking resistance and the like
Or one or more types of Cu. In addition, about addition of Si and Mn for the purpose of deoxidation in the steelmaking process, 0.02 to 2.5% by mass of Si and 0.1% of Mn were added.
It is preferable to adjust in the range of 02 to 3% by mass.

On the other hand, depending on the production method such as addition of a large amount of C to the loom member material, low-temperature quenching or high-temperature tempering,
It was confirmed that the corrosion resistance was impaired, and the improvement method was examined. As a result of investigating the cause of the decrease in the corrosion resistance, Cr in the steel was combined with C and chromium carbide of Cr ₂₃ C ₆ was precipitated. It was found that Cr which was effective for improving corrosion resistance was taken into the carbide by the precipitation of the chromium carbide and Cr near the precipitate was deficient, so that the corrosion resistance was impaired and corroded. In addition, if the quenching temperature or the tempering temperature is inappropriate, not only corrosion resistance but also toughness is greatly affected.

[0015] From these facts, the present inventors have studied variously the best manufacturing method which can be manufactured without impairing the corrosion resistance and toughness of the steel of the present invention. The relation between the quenching temperature, corrosion resistance and toughness of steel materials having various compositions was examined. After quenching heat treatment at various quenching temperatures, the corrosion resistance and toughness of the samples further subjected to tempering treatment at 400 ° C. were investigated, and the results were compared with the quenching temperature and the unbonded k ^* (Ti
FIG. 1 shows a plot obtained by rearranging and plotting the relationship based on the relationship between C and Nb, which is an index indicating the amount of C that could not bind to Nb.

As is apparent from the map shown in FIG. 1, a region excellent in both corrosion resistance and toughness was recognized. this,
As a result of regression calculation of a center line excellent in both characteristics of corrosion resistance and toughness, Expression (1) was obtained as a regression calculation value: T. T = 280 × k ^* + 1200 {(1) where k ^* = log {C% −0.16 (Nb% + Ti%)} (2)

Further, from the regression line of the equation (1), ± 50 ° C.
If the distance is more than the above, excellent corrosion resistance and toughness cannot be obtained. That is, when the regression calculation value is more than ± 50 ° C. away from T,
On the low temperature side, the corrosion resistance is reduced, and on the high temperature side, the toughness is poor. Below the lower limit, the Cr carbide does not completely form a solid solution, and the undissolved Cr carbide serves as a starting point of corrosion, thereby deteriorating the corrosion resistance. On the other hand, if the upper limit is exceeded, the Cr carbide completely dissolves and the corrosion resistance is maintained, but the austenite grains become coarse and adversely affect the toughness after quenching. From the above results, appropriate quenching for obtaining excellent corrosion resistance and toughness needs to be performed within a temperature range of ± 50 ° C. of the regression calculation value T.

Further, it was also found that even when quenching was performed within the optimum temperature range of ± 50 ° C. of the regression calculation value T, the corrosion resistance and toughness sometimes decreased depending on the tempering temperature. Optimal composition (C:
0.32% by mass, Cr: 15.56% by mass, Nb: 0.
FIG. 2 shows the results of investigating the effect of the tempering temperature on corrosion resistance and toughness by changing the quenching temperature of steel having 45% by mass (three levels within the optimum temperature range of ± 50 ° C. of T).

At a tempering temperature of 100 ° C. or less, the steel sheet broke in a bending test, failing to obtain sufficient toughness. Fifteen
When the tempering is performed at a temperature lower than 0 ° C., the distortion of the martensite phase transformed and generated during quenching from a high temperature cannot be sufficiently removed, and the toughness required for a loom member cannot be recovered. But 5
When the temperature exceeded 00 ° C., rust was generated in the salt spray test, and a decrease in corrosion resistance was observed. From this result, it can be confirmed that there is a region where the corrosion resistance and the toughness are impaired depending on the tempering temperature even when the treatment is performed in the optimum quenching temperature range.

That is, in the present invention, excellent corrosion resistance and toughness can be obtained by performing a heat treatment at an optimum quenching temperature and further performing a tempering heat treatment in a range of 150 to 500 ° C. As described above, the optimum manufacturing conditions for obtaining excellent corrosion resistance and toughness by the method of the present invention are as follows:
And a heat treatment at a tempering temperature of 150 to 500 ° C. Here, T is obtained by the above equation (1).

[0021]

The embodiments will be described below. Table 1 shows the main components of the comparative steel and the invention steel. The material is subjected to solution treatment after melting, hot-rolled to a thickness of 5 mm, and 780
After heating at 9 ° C for 9 hours, the furnace was cooled, and pickling, cold rolling, and annealing were repeated to finish the sheet to a thickness of 0.3 mm, which was used as a test material. Test pieces for evaluating abrasion resistance against abrasion caused by fibers were prepared by quenching materials having a thickness of 0.3 mm of comparative steel and invention steel from each temperature above and below regression calculation value T, and 50%. A predetermined quenching / tempering heat treatment of tempering treatment at each temperature of up to 600 ° C. was performed, and the test piece was processed into a flood heald of a loom member.

[0022]

The amount of carbide deposited was measured by the above-described method, and the corrosion resistance, toughness, and wear resistance were evaluated. First, Table 2 shows the results of evaluation of the precipitation amount of Ti carbide and Nb carbide and the wear resistance index M (%) of the steel of the present invention and the comparative steel.
When the addition amounts of Ti and Nb are small as in Comparative Steel Types 6 and 7, precipitation of Ti carbide and Nb carbide is also small, and the wear resistance index M is increased, so that wear resistance cannot be obtained. Ti
When the total precipitation amount of carbides and Nb carbides increases, the wear resistance index M decreases, indicating excellent wear resistance.
FIG. 3 is a graph showing the relationship between the total amount of Ti carbide and Nb carbide deposited and the wear resistance index M. When the total amount of carbide precipitation increases, the wear resistance index M sharply decreases, and the wear resistance index M becomes less than 50% at the boundary of the total carbide precipitation 0.1 mass%, that is, that of the conventional product. As you can get a flood heald with a service life more than twice as long,
As described above, the total amount of carbide precipitated in the method of the present invention is specified to be 0.1% by mass or more.

[0024]

Next, the relationship between the quenching temperature and the tempering temperature and the corrosion resistance and toughness were evaluated. Table 3 shows the results.
Those having a predetermined alloy composition, quenched at a temperature satisfying the formula (1) defined in the present invention, and tempered at a temperature in the range of 150 to 500 ° C. have not only abrasion resistance but also corrosion resistance and toughness. Was also excellent. On the other hand, in Comparative Examples in which the quenching temperature was higher than the specified value, no satisfactory one was obtained in terms of toughness. Further, in the comparative example having a low quenching temperature, no satisfactory corrosion resistance was obtained. Furthermore, a comparative example having a high tempering temperature could not obtain satisfactory corrosion resistance, and a comparative example having a low tempering temperature could not obtain satisfactory toughness. Steel types 6 and 7 have low contents of Ti and Nb which form hard carbide as described above.
Precipitation of Ti carbide and Nb carbide is small, and the intended purpose cannot be achieved in terms of abrasion resistance.

[0026]

[0027]

As described above, according to the method of the present invention, by containing Ti and / or Nb to precipitate a predetermined amount or more of hard carbide, excellent abrasion due to fibers is prevented. Corrosion resistance and toughness can be improved by imparting abrasion resistance and performing quenching and tempering treatments at optimal temperatures. As a result, abrasion of looms caused by the fiber of the woven fabric is a problem, especially at parts where abrasion resistance is required for abrasive wear, such as flat healds, droppers, reed feathers, deformed reeds, and reeds. Measures can be taken, and a great contribution can be expected to extend the service life of this type of related equipment such as a loom machine.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a quenching temperature and corrosion resistance and toughness.

FIG. 2 is a graph showing a relationship between a tempering temperature and corrosion resistance and toughness.

FIG. 3 is a graph showing the relationship between the total precipitation amount of Ti carbide and Nb carbide and wear resistance.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Morikawa 4976 Nomura Minamicho, Shinnanyo-shi, Yamaguchi Prefecture Inside Nisshin Steel Corporation Stainless Steel Business Headquarters (72) Inventor Takashi Yamauchi 4976 Nomuraminamicho, Shinnanyo-shi, Yamaguchi Prefecture Sun New Steel Co., Ltd. Stainless Business Division

Claims (1)

[Claims] 1. Cr: 10 to 18% by mass, C: 0.05
０．５0.5% by mass and further containing Ti and / or N
b: Ti: 0.05 to 1% by mass alone, Nb: 0.05 to 1% by mass alone or Ti + Nb: 0.0 in total amount
A steel containing 5 to 1% by mass and a balance substantially composed of Fe has a quenching temperature of T ± 50 ° C. and a tempering temperature of 150 to 150 with respect to T determined by the following formulas (1) and (2). 5
A heat treatment is performed at 00 ° C. to change the structure of the steel into a martensitic phase and to precipitate and precipitate 0.1% by mass or more of carbides of Ti and / or Nb in a matrix of the steel. A method for manufacturing a material for a high-strength steel loom member having excellent fiber wear properties. Here, T = 280 × k ^* + 1200 {(1) k ^* = log {C% −0.16 (Nb% + Ti%)} (2)