CN100535171C - Copper-carbon easy-cutting stainless steel and method for making same - Google Patents

Abstract

The present invention relates to a process of a free-cutting copper-carbon stainless steel with a weight percentage of chemical compositions as follows: C 0.1-0.6 percent, Cr 10.0-20.0 percent, Cu 1.0-2.0 percent, Mo 0.0-1.2 percent, Si 0.3-0.9 percent, Mn 0.4-1.0 percent, Ni 0.0-2.0 percent and the remainder is Fe. After a heat treatment, the stainless steel of the above chemical compositions is conducted with a quenching treatment at a temperature of 1000-1080 degrees Celsius system, is preserved at the temperature for a period of time, is quenched in oil rapidly, is cooled to below 100 degrees Celsius system, then is aged for 5-10 hours at a temperature of 500-700 degrees Celsius system and then is cooled to the room temperature, and finally the free-cutting copper-carbon stainless steel is obtained. Through the heat treatment the copper-graphite compound phase is formed and distributed evenly in the steel matrix, thereby the cutting performance of the stainless steel is improved.

Description

A kind of copper-carbon easy-cutting stainless steel and preparation method thereof

Technical field

The present invention relates to a kind of copper-carbon easy-cutting stainless steel and preparation method thereof, belong to the alloy steel material preparing technical field.

Background technology

Development along with industries such as Aeronautics and Astronautics, oil and chemical industry, stainless material is used widely, but characteristics such as stainless steel is big owing to toughness, hot strength is high, thermal conductivity is low are difficult to processing, therefore improve the important topic that Machinability of Stainless Steel becomes stainless steel industry.At present, main by adding easily cutting element, for example: sulphur, lead, selenium and tellurium element improve Machinability of Stainless Steel.Yet along with the enhancing of people's environmental consciousness, poisonous elements such as lead, selenium, tellurium will be limited to use on industrial production gradually.Though element sulphur can significantly improve the cutting ability of steel, yet the sulfide inclusion that element sulphur forms in steel can reduce the corrosion resistance nature of steel, corrosion resistance especially, thereby be not suitable in stainless steel, using.For fear of above-mentioned shortcoming, this patent is by adding copper in stainless steel, and, in steel, form the cutting ability that copper, the easy cutting of graphite compound improve steel mutually, and analyze and proposed copper, the compound mechanism that improves the stainless steel cutting performance mutually of graphite by a kind of special thermal treatment process.The Machinability of Stainless Steel of handling through this method has reached the stainless cutting level of sulfur-bearing.

Summary of the invention

The preparation method who the purpose of this invention is to provide a kind of copper-carbon easy-cutting stainless steel.

A kind of preparation method of copper-carbon easy-cutting stainless steel is characterized in that it being that following technological process and step are arranged:

A, this stainless chemical ingredients and weight percent thereof are:

C：0.1～0.6％

Cr：10.0～20.0％

Cu：1.0～2.0％

Mo：0.0～1.2％

Si：0.3～0.9％

Mn：0.4～1.0％

Ni：0.0％～2.0％

Fe: surplus

B, will be by the good admixtion of above-mentioned formulated, be put in the conventional melting method of tradition and carry out melting in electric induction furnace or the electric arc furnace, behind esr, forge or be rolled into the stainless steel steel billet again.

C, above-mentioned steel billet is heat-treated, earlier this steel billet is carried out quench treatment, quenching temperature is 1000～1080 ℃, and is incubated by the time of 1.5min/mm; Rapid then oil quenching is cooled to below 100 ℃;

D and then with steel billet in 500～700 ℃ of following timeliness 5～10 hours, in air, naturally cool to room temperature subsequently; Steel billet after above-mentioned thermal treatment is copper-carbon easy-cutting stainless steel.

The composition design of copper-carbon easy-cutting stainless steel of the present invention and preparation technology's theoretical foundation are as described below:

(1) for the cupric stainless steel, because alloy content is generally all very high, in order in quenching process, to make the steel austenitizing, and make carbide be solidly soluted in the austenite as much as possible, so the selective quenching minimum temperature is 1000 ℃, soaking time is calculated by 1.5min/mm.

(2) because the solubleness of copper in steel is low, often can find in the production that the steel surface can form one deck deposited copper sometimes.If the quenching temperature of steel more than the fusing point (1083 ℃) of copper then this layer copper of surface deposition will form liquid film, is soaked into to steel is inner with the surface of wetting steel and along crystal boundary, cause serious copper to split at last.Therefore, the highest quenching temperature is chosen as 1080 ℃.

(3) be chosen as 500～700 ℃ of timeliness 5～10 hours, help separating out of copper, the compound phase of graphite, and the size that can control copper, the compound phase of graphite is in 10～20nm scope.

(4) control copper is separated out with copper, the compound form mutually of graphite with carbon, and the mean sizes of this phase is in 10～20nm scope, and is even littler, and is scattered in the matrix uniformly.The compound content of graphite in mutually of copper, carbon is 10～20%, even more, and all the other compositions are elemental copper.The compound copper in mutually of copper, graphite can reduce stainless yield strength, thereby makes stainless steel easier generation under the squeezing action of cutter shear viscous deformation, thereby has reduced the wearing and tearing of cutter; Copper, graphite compound mutually in a large amount of graphite it is present in the steel matrix as solid lubricant, in working angles, can lubricate cutter, thereby improve Machinability of Stainless Steel.

Description of drawings

Fig. 1 is the wear of the tool flank-time changing curve comparison diagram of 4Cr13Cu1.4 steel alloy and comparative example 4Cr13 steel and sulfur-bearing 4Cr13 steel in the embodiment of the invention 1.

Fig. 2 is the wear of the tool flank-time changing curve comparison diagram of 4Cr16MoCu1.3 steel alloy and comparative example 4Cr16Mo steel in the embodiment of the invention 2.

Embodiment

After now embodiments of the invention specifically being described in.

Embodiment 1: technological process and step among the embodiment are as follows: the chemical constitution of the copper-carbon easy-cutting stainless steel in the present embodiment is as follows: (wt%)

C 0.4％

Cr 13.0％

Cu 1.4％

Mo 0％

Si 0.42％

Mn 0.70％

Fe 84.08％

Above-mentioned stainless steel is represented with label 4Cr13 Cu1.4.Its preparation process and step are as follows:

(1) will be by the good admixtion of above-mentioned formulated, be put in the conventional melting method of tradition and carry out melting in electric induction furnace or the electric arc furnace, behind esr, forge or be rolled into the stainless steel steel billet again.

(2) above-mentioned steel billet sample is heat-treated, earlier this steel billet is carried out quench treatment, quenching temperature is 1020 ℃ quenches down, and is incubated by the time of 1.5min/mm, and rapid then oil quenching is cooled to take out below 100 ℃, and this moment, its hardness was 52～54HRC.

(3) steel billet after will quenching naturally cools to room temperature subsequently 600 ℃ of following timeliness 5 hours in air, promptly gets copper-carbon easy-cutting stainless steel.

As a comparative example, the stainless steel that does not contain Cu is made comparisons, this chemical ingredients that does not contain the Cu steel is identical with the foregoing description 1 with preparation process, and its chemical ingredients following (wt%): C 0.4%, Cr 13.0%, and Cu 0%, and Mo 0%, Si 0.42%, and Mn 0.70%, and Fe 85.48%.Prepared stainless steel is represented with label 4Cr13.

Embodiment 2: technological process and step in the present embodiment are as follows: the chemical constitution of the copper-carbon easy-cutting stainless steel in the present embodiment is as follows: (wt%)

C 0.4％

Cr 16.0％

Cu 1.3％

Mo 1.0％

Si 0.75％

Mn 0.65％

Fe 79.90％

Above-mentioned stainless steel is represented with label 4Cr16Mo Cu1.3.Its preparation process and step are as follows:

(1) will be by the good admixtion of above-mentioned formulated, be put in the conventional melting method of tradition and carry out melting in electric induction furnace or the electric arc furnace, behind esr, forge or be rolled into the stainless steel steel billet again.

(2) above-mentioned steel billet sample is heat-treated, earlier this steel billet is carried out quench treatment, quenching temperature is 1050 ℃ quenches down, and is incubated by the time of 1.5min/mm, and rapid then oil quenching is cooled to take out below 100 ℃, and this moment, its hardness was 53～55HRC.

(3) steel billet after will quenching naturally cools to room temperature subsequently 650 ℃ of following timeliness 6 hours in air, promptly gets copper-carbon easy-cutting stainless steel.

As a comparative example, the stainless steel that does not contain Cu is made comparisons, this chemical ingredients that does not contain the Cu steel is identical with the foregoing description 2 with preparation process, and its chemical ingredients following (wt%): C 0.4%, Cr 16.0%, and Cu 0%, and Mo 1.0%, Si 0.75%, and Mn 0.65%, and Fe 81.20%.Prepared stainless steel is represented with label 4Cr16Mo.

Performance test: the stainless steel sample of the foregoing description 1 and embodiment 2 gained is done the performance comparison test respectively.

The cutting ability test adopts dried butt formula to carry out on the C6140 lathe; Tool selection YT15 inserted tool; Anterior angle, relief angle and tool cutting edge angle are respectively 75,75 and 75 degree; Perhaps be 30,45 and 45 degree.The wear of the tool flank of the cutter of record under the different cutting times.

Test one: the 4Cr13Cu1.4 free cutting stainless steel of gained among the embodiment 1 and common 4Cr13 steel and the 4Cr13S free-cutting steel of common sulfur-bearing are done the cutting ability test, and compare.Test-results is referring to Fig. 1.Fig. 1 is the wear of the tool flank-time changing curve comparison diagram of each different steel grades.As can be seen from Figure 1, the cutting ability of the 4Cr13Cu1.4 free cutting stainless steel of handling through the inventive method obviously is better than common 4Cr13 steel, and approaches the cutting level of the 4Cr13S free cutting stainless steel of sulfur-bearing.

Test two: the 4Cr16MoCu1.3 free cutting stainless steel of gained among the embodiment 2 and common 4Cr16Mo steel and the 4Cr13S free-cutting steel of common sulfur-bearing are done the cutting ability test, and compare.Test-results is referring to Fig. 2.Fig. 2 is the wear of the tool flank-time changing curve comparison diagram of each different steel grades.As can be seen from Figure 2, the cutting ability of the 4Cr16MoCu1.3 free cutting stainless steel of handling through the inventive method obviously is better than common 4Cr16Mo steel.

Electronic Speculum microanalysis: utilize the projection Electronic Speculum that the form and the size of the copper in the 4Cr13Cu1.4 steel, the compound phase of graphite are observed.The compound phase of copper, graphite that can see in this steel is of a size of about 10nm.From finding out that the main component of this phase is elemental copper and graphite C the spectrogram.The concrete composition of this phase is as shown in table 1 below, and wherein the content of graphite reaches 37%.

The composition of the compound phase of table 1 copper-graphite

Element	Weight %	Atom mol%
			C Cu adds up to	37.54 62.46 100.00	76.07 23.93 100.00

The composition of the compound phase of table 1 copper-graphite

Element	Weight %	Atom mol%
			C Cu adds up to	37.54 62.46 100.00	76.07 23.93 100.00

Claims (1)

1.. the preparation method of a copper-carbon easy-cutting stainless steel is characterized in that this method is that following technological process and step are arranged:

A, this stainless chemical ingredients and weight percent thereof are:

C：0.1～0.6％

Cr：10.0～20.0％

Cu：1.0～2.0％

Mo：0.0～1.2％

Si：0.3～0.9％

Mn：0.4～1.0％

Ni：0.0％～2.0％

Fe: surplus;

B, will be by the good admixtion of above-mentioned formulated, be put in the conventional melting method of tradition and carry out melting in electric induction furnace or the electric arc furnace, behind esr, forge or be rolled into the stainless steel steel billet again.

C, above-mentioned steel billet is heat-treated, earlier this steel billet is carried out quench treatment, quenching temperature is 1000～1080 ℃, and is incubated by the time of 1.5min/mm; Rapid then oil quenching is cooled to below 100 ℃;

D and then with steel billet in 500～700 ℃ of following timeliness 5～10 hours, in air, naturally cool to room temperature subsequently; Steel billet after above-mentioned thermal treatment is copper-carbon easy-cutting stainless steel.

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