阅读说明：本技术 一种轴类工件防渗碳处理方法 (Anti-carburizing treatment method for shaft workpieces ) 是由 殷健 骆波阳 何建平 于 2020-11-27 设计创作，主要内容包括：一种轴类工件防渗碳处理方法,步骤(1)：制作芯轴；步骤(2)：洗涤；步骤(3)装炉；步骤(4)渗碳淬火；步骤(5)清洗；步骤(6)回火；步骤(7)拆炉。本发明可防止渗碳气氛进入防渗区,达到防渗目的；芯轴与工件直接接触,避免了工件与工装接触时异物对工件产生外观影响；使用芯轴,避免了防渗涂料与工件的大面积接触,可以避免偏酸性防渗涂料对工件产生的腐蚀；可以节省防渗涂料的使用量。(An anti-carburizing treatment method for shaft workpieces comprises the following steps of (1): manufacturing a mandrel; step (2): washing; step (3), charging; carburizing and quenching; cleaning; tempering; and (7) disassembling the furnace. The invention can prevent carburizing atmosphere from entering the seepage-proofing area, thereby achieving the aim of seepage proofing; the mandrel is in direct contact with the workpiece, so that the influence of foreign matters on the appearance of the workpiece when the workpiece is in contact with the tool is avoided; the mandrel is used, so that large-area contact between the anti-seepage coating and the workpiece is avoided, and corrosion of the acidic anti-seepage coating to the workpiece can be avoided; the use amount of the anti-seepage coating can be saved.)

1. An anti-carburizing treatment method for shaft workpieces is characterized by comprising the following steps: the method comprises the following steps:

step (1): manufacturing a mandrel: manufacturing a profiling mandrel according to the size of a blind hole of a workpiece, wherein the mandrel is made of 16MnCr5, the outer diameter of the chamfer of the mandrel is the same as the inner diameter of the blind hole of the workpiece, the workpiece is made of 20CrMnTi, the surface hardness is HRC58-63, the depth of a seeping layer is 0.6mm-0.8mm, and the hardness of an inner hole is HRC 37-43;

step (2): washing: washing the anti-carburizing region of the blind hole of the workpiece by using a cleaning agent, and then drying;

step (3), charging: after the workpiece is dried, uniformly smearing impermeable coating at the chamfer angle of the mandrel, and then loading the workpiece into a blind hole of the workpiece to play a role in sealing the blind hole and preventing carburizing;

carburizing and quenching: pushing the workpiece into a carburizing furnace for carburizing, wherein the preheating temperature is 770-780 ℃, the heat preservation time is 20 minutes, the forced infiltration temperature is 905-925 ℃, the heat preservation time is 100 minutes, the carbon potential is 1.10-1.20%, the diffusion temperature is 890-910 ℃, the heat preservation time is 40 minutes, the carbon potential is 0.90-1.00% and 0.95%, pulling the workpiece out for oil quenching, the quenching temperature is 780-800 ℃, the heat preservation time is 40 minutes, the carbon potential is 0.80-0.90%, the oil quenching time is 20 minutes, and the stirring speed is medium speed;

and (5) cleaning: cleaning the quenched workpiece;

step (6) tempering: tempering the cleaned workpiece at 160-180 deg.c for 150 min;

step (7), dismantling the furnace: and taking the tempered workpiece out of the tool, removing the mandrel, and putting the workpiece into a turnover box.

2. The anti-carburizing treatment method for the shaft workpieces according to claim 1, characterized in that: and (3) brushing anti-carburizing coating on the anti-carburizing area of the blind hole of the dried workpiece, and brushing by using a soft brush.

Technical Field

The invention relates to the field of carburizing and quenching heat treatment, in particular to an anti-carburizing treatment for shaft workpieces.

Background

With the rapid development of the new energy automobile industry, the shaft products of the electric automobiles are widely applied, and the shaft weight of some electric automobiles is large, and the design of parts usually pursues the light weight of the products so as to achieve the optimal design. In this regard, designers often design some products such as through holes or blind holes to achieve light weight. In these products, most shafts have some functional dimensions of the internal bore, and these dimensions are very demanding. Many of these products are subjected to a carburizing and quenching heat treatment, which is quite difficult to control the size of the inner bore, and therefore, it is necessary to perform a post heat treatment process on the inner bore.

The inner hole is machined by turning, and in order to make the inner hole easier to machine after heat treatment, the functional hole needs to be subjected to anti-carburizing treatment during carburizing heat treatment so as to reduce the hardness in the hole. The conventional methods for the anti-carburizing treatment are generally coating of a barrier agent, plating of metal, and the like. The existing anti-carburizing treatment method has the defects that: when the anti-seepage agent is used for seepage prevention, if foreign matters are loaded in a tool, the risk of surface defects of the workpiece can be increased by directly contacting the workpiece; (2) when the acidic anti-seepage agent is used for seepage prevention, the surface of a workpiece can be corroded, so that the workpiece is corroded; (3) all the inner hole surfaces need to be coated, the using amount of the impermeable coating is large, and the using cost of the impermeable agent is increased.

Disclosure of Invention

The invention aims to provide an anti-carburizing treatment method for shaft workpieces, which can prevent the workpieces from generating appearance defects when contacting with a tool, reduce the large-area corrosion of coatings on the workpieces and save the dosage of impermeable coatings.

The anti-carburizing treatment method for the shaft workpiece comprises the following steps:

step (1): manufacturing a mandrel: manufacturing a profiling mandrel according to the size of a blind hole of a workpiece, wherein the mandrel is made of 16MnCr5, the outer diameter of the chamfer of the mandrel is the same as the inner diameter of the blind hole of the workpiece, the workpiece is made of 20CrMnTi, the surface hardness is HRC58-63, the depth of a seeping layer is 0.6mm-0.8mm, and the hardness of an inner hole is HRC 37-43;

step (2): washing: washing the anti-carburizing region of the blind hole of the workpiece by using a cleaning agent, and then drying;

step (3), charging: after the workpiece is dried, uniformly smearing impermeable coating at the chamfer angle of the mandrel, and then loading the workpiece into a blind hole of the workpiece to play a role in sealing the blind hole and preventing carburizing;

carburizing and quenching: pushing the workpiece into a carburizing furnace for carburizing, wherein the preheating temperature is 770-780 ℃, the heat preservation time is 20 minutes, the forced infiltration temperature is 905-925 ℃, the heat preservation time is 100 minutes, the carbon potential is 1.10-1.20%, the diffusion temperature is 890-910 ℃, the heat preservation time is 40 minutes, the carbon potential is 0.90-1.00%, pulling the workpiece out for oil quenching, the quenching temperature is 780-800 ℃, the heat preservation time is 40 minutes, the carbon potential is 0.80-0.90%, the oil quenching time is 20 minutes, and the stirring speed is medium speed;

and (5) cleaning: cleaning the quenched workpiece;

step (6) tempering: tempering the cleaned workpiece at 160-180 deg.c for 150 min;

step (7), dismantling the furnace: and taking the tempered workpiece out of the tool, removing the mandrel, and putting the workpiece into a turnover box.

Preferably, for the step (2), the anti-carburizing coating is brushed on the anti-carburizing area of the blind hole of the dried workpiece, and a soft brush is used for brushing.

Compared with the prior art, the invention has the following advantages:

(1) preventing the carburizing atmosphere from entering an anti-seepage area to achieve the anti-seepage purpose;

(2) the mandrel is in direct contact with the workpiece, so that the influence of foreign matters on the appearance of the workpiece when the workpiece is in contact with the tool is avoided;

(3) the mandrel is used, so that large-area contact between the anti-seepage coating and the workpiece is avoided, and corrosion of the acidic anti-seepage coating to the workpiece can be avoided;

(4) the use amount of the anti-seepage coating can be saved.

Drawings

FIG. 1 is a temperature profile of step (4) of an embodiment of the present invention;

FIG. 2 is a schematic illustration of a product in an embodiment of the invention;

FIG. 3 is a schematic view of a mandrel in an embodiment of the present invention;

FIG. 4 is a schematic view of the application area of the barrier agent of the present invention;

FIG. 5 is a schematic view of a workpiece of the present invention in direct contact with a mandrel;

Detailed Description

In the schematic diagrams of the invention shown in fig. 1 to 5, the steps of the anti-carburizing treatment method for the shaft workpiece are as follows:

step (1): manufacturing a mandrel: manufacturing a profiling mandrel according to the size of a blind hole of a workpiece, wherein the mandrel is made of 16MnCr5, the outer diameter of the chamfer of the mandrel is the same as the inner diameter of the blind hole of the workpiece, the workpiece is made of 20CrMnTi, the surface hardness is HRC58-63, the depth of a seeping layer is 0.6mm, and the hardness of an inner hole is HRC 37-43;

step (2): washing: washing the anti-carburizing region of the blind hole of the workpiece by using a cleaning agent, and then drying;

step (3), charging: after the workpiece is dried, brushing and uniformly smearing the anti-carburizing paint at the chamfer of the mandrel by using a soft brush, and then loading the anti-carburizing paint into the blind hole of the workpiece to play a role in sealing the blind hole and preventing carburizing;

carburizing and quenching: pushing the workpiece into a carburizing furnace for carburizing, wherein the preheating temperature is 780 ℃, the heat preservation time is 20 minutes, the strong infiltration temperature is 915 ℃, the heat preservation time is 100 minutes, the carbon potential is 1.15 percent, the diffusion temperature is 900 ℃, the heat preservation time is 40 minutes, the carbon potential is 0.95 percent, pulling the workpiece out for oil quenching, the quenching temperature is 790 ℃, the heat preservation time is 40 minutes, the carbon potential is 0.85 percent, the oil quenching time is 20 minutes, and the stirring speed is medium speed;

and (5) cleaning: cleaning the quenched workpiece;

step (6) tempering: tempering the cleaned workpiece at 170 deg.c for 150 min;

step (7), dismantling the furnace: and taking the tempered workpiece out of the tool, removing the mandrel, and putting the workpiece into a turnover box.

The hardness after seepage prevention is compared by using the anti-carburizing treatment method for the shaft workpieces, and the detection results are shown in the following table 1:

TABLE 1

The hardness requirement after seepage control is HRC37-43, and the hardness is in the qualified range.

By using the anti-carburizing treatment method for the shaft workpiece, after heat treatment, the size of the hole is compared with the roundness sizes (phi 24 and phi 18) of the hole after coating seepage prevention, and the comparison result is shown in Table 2:

TABLE 2

By using the anti-carburizing treatment method for the shaft workpieces, the roundness of phi 24 holes is 3.7 microns, and the roundness of phi 18 holes is 5.6 microns before heat treatment. Before the anti-seepage heat treatment of the anti-seepage coating, the roundness of phi 24 holes is 4.7 mu m, and the roundness of phi 18 holes is 6.2 mu m. 3) The deformation in the hole meets the processing requirement.

Therefore, the shaft workpiece anti-carburizing treatment method has no corrosion phenomenon in the hole after seepage prevention.