阅读说明：本技术 一种变截面零部件的一体成型加工工艺 (Integrated forming processing technology of variable cross-section parts ) 是由 关铁 于 2019-02-28 设计创作，主要内容包括：本发明公开了一种变截面零件的一体成型加工工艺,其变截面辊锻成形包括以下具体步骤：a.根据变截面零件的形状制定轧制工艺,并按照轧制工艺安排轧机先后顺序进行多道次辊锻成形；b.将金属材料预先加热,送至轧机后,经过变截面加工,按照金属材料输送方向进行辊锻,所述金属材料从一个轧机转移到另一个轧机前,进行补热处理,重新加热,然后送进下一个轧机进行轧制。本发明提供了一种变截面零件的加工工艺,采用变截面辊锻一体化成形技术,所制备变截面零件,相对于组合式或焊接式的变截面零部件,具有较高力学性能和使用寿命。(The invention discloses an integrated forming processing technology of a variable cross-section part, wherein the variable cross-section roll forging forming comprises the following specific steps: a. a rolling process is established according to the shape of the variable cross-section part, and the rolling mill is arranged to perform multi-pass roll forging forming in sequence according to the rolling process; b. preheating a metal material, feeding the metal material to a rolling mill, performing variable cross-section processing, performing roll forging according to the conveying direction of the metal material, performing heat supplementing treatment before transferring the metal material from one rolling mill to another rolling mill, reheating the metal material, and feeding the metal material to the next rolling mill for rolling. The invention provides a processing technology of a variable cross-section part, which adopts a variable cross-section roll forging integrated forming technology to prepare the variable cross-section part, and compared with a combined or welded variable cross-section part, the variable cross-section part has higher mechanical property and longer service life.)

1. An integrated forming processing technology of a variable cross-section part comprises the following specific steps:

a. setting a rolling process according to the shape of the variable cross-section part, and arranging a rolling mill to perform multi-pass roll forging forming in sequence according to the rolling process, wherein the rolling mill comprises a plurality of groups of roller variable cross-section forming units, and the roller distance between roller pairs is independently and adjustably arranged;

b. after the metal material is sent to a rolling mill, the metal material is subjected to variable cross section processing, rolling and forging are integrally formed according to the conveying direction of the metal material, and the metal material is subjected to heat supplementing treatment before being transferred from one rolling mill to the other rolling mill and then sent to the next rolling mill for rolling.

2. The process for integrally forming a variable cross-section part according to claim 1, wherein the material blank is a single material, a double single material or a plurality of single materials, and the single materials are all commercially available metals.

3. The process of claim 2, wherein the metal of the variable cross-section part includes but is not limited to frog, point rail, and guard rail.

4. The integrated forming process for variable cross-section parts according to claim 2, wherein each set of roller variable cross-section forming units comprises at least two rollers.

5. The integrated forming process of variable cross-section parts according to claim 2, wherein the roller variable cross-section forming unit comprises a top roller, a bottom roller, a left roller and a right roller.

6. The process for integrally forming a variable cross-section part according to claim 1, wherein the specific steps further comprise preparation of a metal material.

7. The process for integrally forming a variable cross-section part according to claim 6, wherein the preparation of the metal material comprises the following steps:

a. firstly, cleaning the inner and outer surfaces of a water-cooled crystallizer, removing metal oxide skin on the surface, and starting electroslag casting after cleaning;

b. the power supply of the electroslag furnace is started, a pair of graphite electrodes are firstly installed on a mechanical rocker arm, then the graphite electrodes are electrified to melt slag to form a slag bath, the rocker arm is lifted, the graphite electrodes are replaced, a rail steel electrode bar is replaced as a consumable electrode, the electrode bar is electrified to melt in the slag bath, a new rail steel electrode bar is replaced after the electrode bar is completely melted, the process is repeated until the specified weight is reached, when all metal liquid drops pass through the slag bath, namely the electrode bar is melted to form a molten bath, the temperature is kept for a period of time, and then metal material blanks are formed in a crystallizer under the forced cooling of circulating water.

8. The integrated forming process for variable cross-section parts according to claim 1, wherein the working surface of the roller wheel, which is in contact with the metal material, is provided with a groove or a convex groove respectively.

Technical Field

The invention relates to the field of material preparation, in particular to an integrated forming processing technology of a variable cross-section part.

Background

In a rail transit system, a turnout is connected with a circuit and a cross station track, so that a locomotive vehicle is switched from one station track to another station track, and the turnout is important basic equipment for ensuring normal, safe and efficient running of a train and has a large quantity. According to statistics, the average mileage per kilometer in an urban subway system corresponds to 1 set of turnouts. The method is characterized in that 10 railway track-changing turnout manufacturers in China are counted, the annual output of a large freight railway in 2017 is 3 ten thousand groups, the annual output value is more than 100 million yuan, and the total market demand of urban railways and high-speed railways which are rapidly developed in recent years is more than 200 million yuan. The switch mainly comprises a frog, a switch rail, a guard rail, a point switch and the like, and comprises two types of parts, namely a uniform section part and a large variable section part. The load of large variable cross-section parts such as frog, switch rail, guard rail and the like is uneven due to the structure and working conditions, local failure is easy to occur, the service life of the large variable cross-section parts is far shorter than that of I-shaped steel rails with uniform cross sections, the large variable cross-section parts are the parts with the most serious damage in a rail structure, the work performance of the large variable cross-section parts affects and determines the safety and the running efficiency of the rail, and the large variable cross-section parts become a bottleneck limiting the rapid development of the rail traffic to the passenger traffic high speed and freight. In view of the above, it is urgent to break through the existing materials, technologies and equipment and develop new materials, new technologies, new processes and new equipment for the large variable cross-section track parts with long service life.

Aiming at the characteristic that the variable cross-section track parts are easy to overload locally and fail prematurely, the current research and development mainly adopts means of assembling, combining or welding after alloy steel is locally reinforced, so that the overall service life of the variable cross-section track parts is prolonged. Taking the frog part in the turnout as an example, fixed frog is mainly used, and the fixed frog comprises a high manganese steel combined type, a high-density integral-casting manganese steel frog, a steel rail combined type and the like, and the foreign high manganese steel combined frog accounts for more than 80% of the frog used on the main line. The high manganese steel integrally cast frog widely used at present has high production efficiency, good integral performance and low price, but has poor wear resistance and higher service life discreteness. In order to improve the wear resistance and the contact fatigue resistance, a locally enhanced high-strength bainite alloy steel frog is further developed. In 1996, J9 bainite steel was developed in the united states to produce fabricated frog elements with better wear resistance. Subsequently, in 2001, german federal railway company (DB) and the austempered steel group (BWG) selected 17 bainite steels used worldwide for comparative testing, and concluded in 2009 that high strength bainite steels were suitable for railway frog applications. Although the mechanical property is excellent enough to meet the heavy-load requirement of railways, the turnout using the bainite steel frog mainly adopts an assembled structure in preparation, and has complex processing and poor integrity. In particular, the inconsistent composition of the frog and the rail alloy imposes severe requirements on welding during installation and replacement.

The high-strength bainite-enhanced variable cross-section rail part has higher mechanical property and longer service life, so the application of the high-strength bainite-enhanced variable cross-section rail part in rail transit is gradually increased, but the high-strength bainite-enhanced variable cross-section rail part is limited by the current manufacturing process, only a combined type or a welding type can be adopted, the combined or welded joint becomes a weak link, and the weak parts are easy to generate local wear fatigue failure in the service process, so the overall service life is influenced.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide an integrated forming processing technology of a variable cross-section part, and the technology is used for manufacturing a large variable cross-section part for rail transit, which has long service life, strong weldability and high reliability.

In order to solve the technical problems, the technical scheme of the invention is as follows:

an integrated forming processing technology of variable cross-section parts, wherein the variable cross-section roll forging forming comprises the following specific steps:

a. setting a rolling process according to the shape of the variable cross-section part, and arranging a rolling mill to perform multi-pass roll forging forming in sequence according to the rolling process, wherein the rolling mill comprises a plurality of groups of roller variable cross-section forming units, and the roller distance between roller pairs is independently and adjustably arranged;

b. after the metal material is sent to a rolling mill, the metal material is subjected to variable cross section processing, rolling and forging are integrally formed according to the conveying direction of the metal material, and the metal material is subjected to heat supplementing treatment before being transferred from one rolling mill to the other rolling mill and then sent to the next rolling mill for rolling.

Further, the material blank is single monomer, double monomer and multiple monomer, and the species is all metals on the market.

Further, the variable cross-section part metal includes, but is not limited to, frog, switch rail, and guard rail.

Furthermore, each set of roller variable cross-section forming unit at least comprises two rollers.

Further, the roller variable cross-section forming unit comprises a top roller, a bottom roller, a left side roller and a right side roller.

Further, the specific steps also comprise the preparation of a metal material.

Further, the preparation of the metal material comprises the following steps:

a. firstly, cleaning the inner and outer surfaces of a water-cooled crystallizer, removing metal oxide skin on the surface, and starting electroslag casting after cleaning;

b. the power supply of the electroslag furnace is started, a pair of graphite electrodes are firstly installed on a mechanical rocker arm, then the graphite electrodes are electrified to melt slag to form a slag bath, the rocker arm is lifted, the graphite electrodes are replaced, a rail steel electrode bar is replaced as a consumable electrode, the electrode bar is electrified to melt in the slag bath, a new rail steel electrode bar is replaced after the electrode bar is completely melted, the process is repeated until the specified weight is reached, when all metal liquid drops pass through the slag bath, namely the electrode bar is melted to form a molten bath, the temperature is kept for a period of time, and then metal material blanks are formed in a crystallizer under the forced cooling of circulating water.

Furthermore, the working surface of the roller wheel, which is contacted with the metal material, is respectively provided with a groove or a convex groove.

The invention can obtain the following beneficial effects:

(1) the invention provides an integrated forming processing technology of a variable cross-section part, which adopts a variable cross-section roll forging integrated forming technology to prepare the variable cross-section part, has higher mechanical property and longer service life compared with combined or welded variable cross-section parts, and can better meet the requirements of actual production;

(2) the invention provides an integrated forming processing technology of variable cross-section parts, which can design and produce products with different widths, different heights and different cross sections according to different shapes of cams, and has the advantages of strong flexibility, simplicity, practicability, low production cost, good quality and stronger adaptability.

Detailed Description

The austempered steel alloy of the present invention and the method for producing the same will be described in detail with reference to the following embodiments.