阅读说明：本技术 一种珠光体球墨铸铁圆柱类零件的镶套方法 (Bushing method for pearlite nodular cast iron cylindrical part ) 是由 尹杰 叶淳健 叶艺明 张沧 于 2019-10-22 设计创作，主要内容包括：本发明公开了一种珠光体球墨铸铁圆柱类零件的镶套方法,包括去除待镶嵌零件的镶嵌外表面变质层和/或缺陷；根据待嵌套零件加工后的镶嵌外表面的尺寸,加工珠光体球墨铸铁镶嵌套的内表面与待镶嵌零件的镶嵌外表面形成过盈配合；将内表面加工后的珠光体球墨铸铁镶嵌套匀速加热至230～280℃并保温到透烧；将透烧后的珠光体球墨铸铁镶嵌套出炉并快速、准确的套在待镶嵌零件的外表面。本发明根据珠光体球墨铸铁的金相组织特点及膨胀特性,根据镶嵌套的壁厚及结构不同针对性采用中低温加热使之膨胀,而后快速、准确的完成嵌套,从而达到强化嵌套后零件表面以延长使用寿命、节约材料、降低使用成本的目的,具有操作简单、嵌套后稳固可靠的特点。(The invention discloses a bushing method of a pearlite nodular cast iron cylindrical part, which comprises the steps of removing a deteriorated layer and/or defects on the embedded outer surface of the part to be embedded; according to the size of the outer surface of the part to be embedded after being processed, the inner surface of the processed pearlite nodular cast iron embedded sleeve is in interference fit with the outer surface of the part to be embedded; heating the pearlite nodular cast iron insert sleeve with the processed inner surface to 230-280 ℃ at a constant speed, and preserving heat until thorough burning; and discharging the fully-burnt pearlite nodular cast iron embedding sleeve out of the furnace and quickly and accurately sleeving the fully-burnt pearlite nodular cast iron embedding sleeve on the outer surface of a part to be embedded. According to the invention, according to the metallographic structure characteristics and the expansion characteristics of the pearlite nodular cast iron, medium-low temperature heating is adopted to expand the embedded sleeve according to different pertinences of the wall thickness and the structure of the embedded sleeve, and then the embedding is completed quickly and accurately, so that the purposes of strengthening the surface of the embedded part to prolong the service life, saving materials and reducing the use cost are achieved, and the embedded pearlite nodular cast iron has the characteristics of simplicity in operation and stability and reliability after the embedding.)

1. A bushing method of a pearlite nodular cast iron cylindrical part is characterized by comprising the steps of part processing to be nested, bushing processing, bushing heating and nesting, and specifically comprises the following steps:

A. processing parts to be nested: removing the deterioration layer and/or the defect of the outer surface of the part to be inlaid;

B. processing an embedding sleeve: according to the size of the outer surface of the part to be embedded after being processed, the inner surface of the processed pearlite nodular cast iron embedded sleeve is in interference fit with the outer surface of the part to be embedded;

C. heating an embedding sleeve: heating the pearlite nodular cast iron insert sleeve with the processed inner surface to 230-280 ℃ at a constant speed, and preserving heat until thorough burning;

D. nesting: and vertically fixing the part to be embedded on the fixed seat, discharging the fully-burnt pearlite nodular cast iron embedding sleeve out of the furnace, quickly and accurately vertically sleeving the embedded outer surface of the part to be embedded, and cooling and fastening.

2. The bushing method of pearlite nodular cast iron cylindrical parts according to claim 1, characterized in that the outer surface of the to-be-inlaid part is machined to a positive tolerance and the surface roughness Ra value is not more than 1.6 μm in said a step.

3. The bushing method for pearlite nodular cast iron cylindrical parts according to claim 2, wherein the inner surface of the pearlite nodular cast iron bushing in step B is machined to a negative tolerance with a surface roughness Ra value of not more than 1.6 μm.

4. The bushing method for pearlite nodular cast iron cylindrical parts according to claim 3, wherein the interference between the inner surface of the pearlite nodular cast iron bushing and the outer surface of the part to be embedded in the step B is 0.20-0.35 mm.

5. The bushing method for pearlite nodular cast iron cylindrical parts according to any one of claims 1 to 4, wherein the pearlite nodular cast iron bushing in the step C is heated to 230 to 280 ℃ and kept warm for 1 to 2 hours.

6. The bushing method for pearlite nodular cast iron cylindrical parts according to claim 5, wherein the heating rate of the pearlite nodular cast iron bushing in the step C is 60-80 ℃/h.

7. The bushing method for pearlite nodular cast iron cylindrical parts according to claim 6, wherein the bushing for pearlite nodular cast iron in step D is completed at a temperature of not less than 200 ℃.

8. The bushing method for pearlite nodular cast iron cylindrical parts according to claim 6, wherein the deviation of the inner surface of the pearlite nodular cast iron after the bushing is taken out of the furnace in step D is measured and is at least 0.35mm larger than the deviation of the outer surface of the part to be embedded.

9. The bushing method for pearlite nodular cast iron cylindrical parts according to claim 5, wherein the inner surface of the bushing of pearlite nodular cast iron in the step C is coated with an antioxidant paint.

10. The bushing method for pearlite nodular cast iron cylindrical parts according to claim 5, wherein the stopping surface of the fixing base in step D supports the lower end of the outer surface of the part to be embedded and has an outer diameter larger than that of the outer surface of the part to be embedded, the middle of the fixing base is provided with a hole penetrating through the lower structure of the part to be embedded, and the hole side of the fixing base is provided with a fastener for adjusting and fixing the verticality of the part to be embedded.

Technical Field

The invention belongs to the technical field of mechanical manufacturing processes, and particularly relates to a bushing method of a pearlite nodular cast iron cylindrical part, which is simple to operate, is stable and reliable after being nested, and can strengthen the surface of the part after being nested so as to prolong the service life, save materials and reduce the use cost.

Background

The nodular cast iron is a high-strength cast iron material of spheroidal graphite obtained by spheroidizing and inoculation, and because the carbon (graphite) exists in the cast iron matrix in a spheroidal shape, the splitting effect of the carbon (graphite) on the matrix is improved, the tensile strength, the yield strength, the plasticity and the impact toughness of the nodular cast iron are greatly improved, and the nodular cast iron has the advantages of wear resistance, shock absorption, good process performance, low cost and the like, is successfully used for casting parts which are stressed complexly and have higher requirements on strength, toughness and wear resistance, and is a cast iron material which is second only to gray cast iron and is widely applied.

Pearlite nodular cast iron (Pearlite heat-resisting steel) is a nodular cast iron in which Pearlite accounts for 80% or more of the matrix structure. The high-strength wear-resistant steel plate contains more pearlite structures, has the characteristics of high strength, moderate hardness, and good plasticity and toughness, and is mainly used for manufacturing parts which have high required strength and certain fatigue strength and wear resistance, such as diesel engine crankshafts, connecting rods, rollers and the like.

In the industries of modern metallurgy, cement and the like, a large amount of nodular cast iron materials are applied to rollers, compression rollers or cylindrical parts, and pearlite nodular cast iron is also adopted with higher requirement. In the whole production process of the industry, the consumption part of cylindrical parts such as a roller, a press roller or a shaft and the like caused by abrasion accounts for about 10-20% of the total weight of the roller. Therefore, how to increase the service life of the cylindrical parts is one of the key problems of effectively reducing the production cost. In the prior art, the solution to the problem generally starts from two aspects; (1) the hardness and the wear resistance of the material of each easily-consumed part are improved, and the service life of each easily-consumed part is prolonged; (2) the method has the advantages that the deformation, abrasion or old roller or rod is repaired, the utilization rate of the roller or rod is improved, and the cost is reduced, so that the method is an important way for reducing the cost of manufacturing products. The hardness and the wear resistance of the part material are integrally improved, a complex heat treatment process and expensive materials are often needed, the process is complex, and the cost is high. The repair is generally carried out by surfacing or embedding according to equipment conditions and production processes, has low repair cost and good effect, and is a repair technology widely adopted at home and abroad. Although the surfacing repair is short and quick, welded parts are easy to deform, so that the use precision is influenced, and the surfacing repair time is too long. The bushing is made of the same material, according to the principle of expansion with heat and contraction with cold, the repaired part is sleeved with the bushing by the change of the size of the inner hole after heating, the bushing and the repaired part are tightly hooped into a whole after cooling, the size requirement before use is met after processing, the performance is unchanged, the precision is higher, and the bushing can adapt to common adoption. However, for metal materials with special structures such as pearlite and the like, too high heating temperature can cause structure transformation, so that the physical properties of the materials are changed, and lower temperature can cause longer heating and heat preservation time, so that not only is the energy consumption high and the efficiency low, but also the oxidation of the surface of the metal materials is easily caused to influence the nesting precision and the surface hardness, and measures such as protective atmosphere and the like are often required to be taken to avoid the oxidation, so that the nesting process cost is increased, and the adaptability of equipment for implementing heating nesting is reduced.

Disclosure of Invention

The invention aims to provide the bushing method of the pearlite nodular cast iron cylindrical part, which is simple to operate, is stable and reliable after being nested, can strengthen the surface of the part after being nested so as to prolong the service life, save materials and reduce the use cost.

The method comprises the steps of processing parts to be nested, processing an embedding sleeve, heating the embedding sleeve and nesting, and specifically comprises the following steps:

A. processing parts to be nested: removing the deterioration layer and/or the defect of the outer surface of the part to be inlaid;

B. processing an embedding sleeve: according to the size of the outer surface of the part to be embedded after being processed, the inner surface of the processed pearlite nodular cast iron embedded sleeve is in interference fit with the outer surface of the part to be embedded;

C. heating an embedding sleeve: heating the pearlite nodular cast iron insert sleeve with the processed inner surface to 230-280 ℃ at a constant speed, and preserving heat until thorough burning;

D. nesting: and vertically fixing the part to be embedded on the fixed seat, discharging the fully-burnt pearlite nodular cast iron embedding sleeve out of the furnace, quickly and accurately vertically sleeving the embedded outer surface of the part to be embedded, and cooling and fastening.

The invention has the beneficial effects that:

1. according to the invention, the heating speed of 60-80 ℃/h is pertinently adopted to heat the mosaic sleeve according to the metallographic structure characteristics and the expansion characteristics of the pearlite nodular cast iron and the wall thickness and the structure of the mosaic sleeve, thereby avoiding the defects and even cracks caused by overhigh heating speed in the prior art, and the medium and low temperature heating of 230-280 ℃ is adopted to expand the sleeve, and then the nesting is completed quickly and accurately, while ensuring that the pearlite structure in the pearlite nodular cast iron insert sleeve is not transformed by heating and even the material is softened, can ensure enough inlay expansion amount and rigidity of the inlay sleeve, and can also reduce heating energy consumption and heating time, therefore, the characteristics of high strength, moderate hardness, and good plasticity and toughness of the nodular cast iron can be maintained, and the purposes of prolonging the service life, saving materials and reducing the use cost of the parts after the parts are strengthened and nested are achieved.

2. The invention can ensure the mechanical property of the inlaid pearlite nodular cast iron sleeve after being inlaid, and can further improve the matrix structure through heating and heat preservation, and the hardness of the repaired piece reaches HRC 44-48 through measurement.

3. The nesting step is simple to operate and convenient to implement, is stable and reliable after nesting, can be suitable for newly manufactured cylindrical parts needing surface strengthening, and can simplify the structure and reduce the cost of high-value materials; the method can also be suitable for repairing deformed or worn old rollers or old rods, effectively improves the utilization rate of the old rollers or the old rods, reduces the cost of consumables and improves the resource utilization rate.

Drawings

FIG. 1 is a diagram illustrating a nesting process according to an embodiment of the present invention;

in the figure: 1-roller, 2-embedded sleeve and 3-fixed seat.

Detailed Description

The invention is further illustrated by the following figures and examples, which are not intended to limit the invention in any way, and any variations or modifications which are based on the teachings of the invention are intended to be within the scope of the invention.

As shown in fig. 1, the method comprises the steps of processing parts to be nested, processing an embedding sleeve, heating the embedding sleeve and nesting, and specifically comprises the following steps:

A. processing parts to be nested: removing the deterioration layer and/or the defect of the outer surface of the part to be inlaid;

B. processing an embedding sleeve: according to the size of the outer surface of the part to be embedded after being processed, the inner surface of the processed pearlite nodular cast iron embedded sleeve is in interference fit with the outer surface of the part to be embedded;

C. heating an embedding sleeve: heating the pearlite nodular cast iron insert sleeve with the processed inner surface to 230-280 ℃ at a constant speed, and preserving heat until thorough burning;

D. nesting: and vertically fixing the part to be embedded on the fixed seat, discharging the fully-burnt pearlite nodular cast iron embedding sleeve out of the furnace, quickly and accurately vertically sleeving the embedded outer surface of the part to be embedded, and cooling and fastening.

And in the step A, the mosaic outer surface of the part to be inlaid is processed to a positive tolerance, and the surface roughness Ra value is not more than 1.6 mu m.

And B, processing the inner surface of the pearlite nodular cast iron mosaic sleeve to a negative tolerance in the step B, wherein the surface roughness Ra value is not more than 1.6 mu m.

And in the step B, the interference magnitude between the inner surface of the pearlite nodular cast iron embedding sleeve and the embedding outer surface of the part to be embedded is 0.20-0.35 mm.

And C, heating the pearlite nodular cast iron insert sleeve to 230-280 ℃ and preserving heat for 1-2 hours.

And C, heating the pearlite nodular cast iron insert sleeve at a heating speed of 60-80 ℃/h.

And D, finishing inlaying the pearlite nodular cast iron inlaying sleeve at the temperature of not less than 200 ℃.

And D, measuring the deviation of the inner surface of the pearlite nodular cast iron after the pearlite nodular cast iron is inlaid and sleeved out of the furnace, wherein the deviation is at least 0.35mm greater than the deviation of the inlaid outer surface of the part to be inlaid.

And C, coating an anti-oxidation coating on the inner surface of the pearlite nodular cast iron embedding sleeve.

And D, supporting the lower end of the outer surface of the part to be embedded by the stop surface of the fixed seat in the step D, wherein the outer diameter of the stop surface is larger than that of the outer surface of the part to be embedded, a hole penetrating through a lower structure of the part to be embedded is formed in the middle of the fixed seat, and a fastener for adjusting and fixing the verticality of the part to be embedded is arranged on the side of the hole of the fixed seat.

The invention also comprises a step of processing the outer surface and/or the end surface of the inlaid pearlite nodular cast iron mosaic sleeve to a specified size.