CN102011057A - CrMnTi series gear steel and processing technique thereof - Google Patents

Abstract

The invention discloses a CrMnTi series gear steel, which consists of the following components in percentage by weight: 0.16 to 0.23 percent of C, 0.20 to 0.37 percent of Si, 0.80 to 1.25 percent of Mn, 1.00 to 1.45 percent of Cr, 0.015 to 0.035 percent of S, 0 to 0.035 percent of P, 0.01 to 0.02 percent of V, 0.04 to 0.10 percent of Ti, 0.015 to 0.035 percent of Al, 0 to 0.25 percent of Ni, 0 to 0.20 percent of Cu, 0 to 0.04 percent of Mo and the balance of Fe and impurities. The gear steel is processed by a special technique. The gear steel manufactured by using the formula and the processing technique has the characteristics of low cost, simplified process, stable quenching property, high production efficiency, good mechanical property and long service life, and is easy to process.

Description

A kind of CrMnTi is Pinion Steel and complete processing thereof

Technical field

The present invention relates to a kind of Pinion Steel and working method thereof, more specifically, is that a kind of CrMnTi is Pinion Steel and complete processing thereof.

Background technology

Pinion Steel is close the knot steel a kind of, is to use one of critical material of having relatively high expectations in the Special Alloy Steel in automobile, railway, boats and ships, the engineering machinery, and be the manufactured materials that guarantees the core component of safety.In recent years, Pinion Steel just towards high-performance, long lifetime, gear operate steadily, directions such as low noise, security, low cost, easily processing, many kinds develop.

CN101289731A discloses a kind of CrMnTi narrow hardenability strip pinion and manufacture method thereof, by to smelting narrow Composition Control, the permanent pulling rate control of continuous casting, be rolled into the Pinion Steel round steel through controlled rolling and controlled cooling again, it is inhomogeneous mainly to solve steel product ingredient, and dense structure, tiny, the terminal hardenability band of crystal grain are narrow, high purity, problem that surface quality is good.

CN1664150 discloses the manufacture method that relates to a kind of sulfur-containing free-cutting pinion steel and steel pipe thereof, adopts specific raw material to become steel pipe by smelting, static ingot, split rolling method, and it rolls the back attitude and is organized as ferrite and adds perlite.

CN1554791 discloses a kind of hardening capacity of Pinion Steel and method of hot workability of improving, it is characterized in that the P content in the control molten steel in the electrosmelting process, P content during tapping in the molten steel is≤0.017%, P content in ladle refining furnace adding ferrorphosphorus adjustment molten steel is controlled between 0.018%～0.026% finished product P content.

CN1851024 discloses a kind of manufacture method of heavy-load gear steel, but owing to adopted noble metal elements such as Ni, Mo in its raw material, makes its manufacturing cost too high, is unsuitable for mass production.

CN101096742 discloses a kind of high-strength pinion steel for vehicles, does not conform to V, and its comprehensive mechanical property haves much room for improvement, thereby further prolongs its work-ing life.

Automatization along with machine line, in order to improve constantly the needs of labour productivity, adaptation high speed program controlled machine tool, require Pinion Steel to have good free cutting property, therefore, work out high-performance, low cost, easily the Pinion Steel of processing and long service life is the problem that this area needs to be resolved hurrily.

Summary of the invention

It is Pinion Steel and complete processing thereof that the object of the invention is to provide a kind of CrMnTi, by adopting unique prescription and complete processing, make that hardening capacity is stable, mechanical property is good, the easy Pinion Steel of processing and long service life, cost is low, operation is simplified, the production efficiency height.

The present invention realizes by following technique means:

A kind of CrMnTi is a Pinion Steel, it is characterized in that, contain following component by weight percentage: 0.16%～0.23% C, 0.20%～0.37% Si, 0.80%～1.25% Mn, 1.00%～1.45% Cr, 0.015%～0.035% S, 0～0.035% P, 0.01%～0.02% V, 0.04%～0.10% Ti, 0.015%～0.035% Al, 0～0.25% Ni, 0～0.20% Cu, 0～0.04% Mo and the Fe and the impurity of surplus.

CrMnTi of the present invention is the Pinion Steel complete processing, may further comprise the steps:

(1) refining just: get the raw materials ready by the described proportioning of claim 1, raw material sent into just under 1640～1670 ℃, smelt in the furnace, the content of regulating C during smelting endpoint is 0.06%～0.10%, adopt slide plate pushing off the slag tapping to realize slag free tapping, tapping process adopts strong deoxidation to combine with pre-deoxidation;

(2) refining: surplus the sending in the ladle refining furnace (LF stove) of watering that produces in the step (1) treated to carry out the reheat refining, killing in the purified molten steel, make white slag fast, control slag basicity is 2.5～3.5, and sulphur content is 0.02%～0.035%, and refining time is no less than 36 minutes;

(3) feed silicon-calcium wire: with the speed feeding silicon-calcium wire (Φ 13mm) of 2～5m/s, soft blow is more than 10 minutes then in molten steel, and the control sulphur content is 0.015%～0.035% when leaving from station;

(4) continuous pouring: under 15～30 ℃ low overheat environment, adopt technologies such as the permanent pulling rate of constant temperature, liquid level are controlled automatically, crystallizer induction stirring, use big bag long nozzle (+argon envelope), submerged nozzle, middle covering agent (special-purpose insulating covering agent+carbonization rice husk), crystallizer protecting residues etc. carry out the full guard cast to molten steel, obtain qualified continuously cast bloom;

(5) rolling: after continuously cast bloom is heated to 1130～1210 ℃ it is rolled, wherein, start rolling temperature is 1040～1100 ℃, and finishing temperature is 850～950 ℃;

(6) aftertreatment: for the blank of specification≤60mm, adopt the bar stacking slow cooling, slow cooling speed is 1.2～1.8 ℃/min; For the blank of specification＞60mm, adopt the slow cooling box slow cooling, slow cooling speed is 0.6～1.2 ℃/min, obtains finished product.

The present invention adopts specific component prescription; on general furnace just, smelt by common process for making; molten steel is to LF stove refining teacher; under the situation that does not add sulphur iron; wait in the purified molten steel in the surplus LF of the turning back to stove by the big bag of continuous casting is watered; the deoxidation degree of control molten steel and the basicity of slag; making the sulphur content in the steel is between 0.02%～0.035%; then carry out the cast of line feeding soft blow and full guard; the sulphur content of the strand spare that obtains is 0.015%～0.035%; be rolled into bar through the steel rolling controlled rolling and cooling, last slow cooling obtains finished product after the assay was approved.Compare with traditional Pinion Steel and complete processing thereof, composition of raw material of the present invention is more reasonable, has realized having guaranteed the comprehensive mechanical property of finished product again simultaneously cheaply, and has been easy to processing; In addition, adopted the big bag of continuous casting to water in the complete processing of the present invention and surplus sulphur content in the steel has been controlled, and, improved the processing characteristics of steel, made finished product be easy to cutting by measures such as steel rolling controlled rolling and cooling, slow cooling; Simplify operation with respect to traditional technology, effectively reduced the smelting production cost, improved working (machining) efficiency.

Embodiment

Below further describe the present invention by embodiment, as known by the technical knowledge, the present invention also can describe by other the scheme that does not break away from the technology of the present invention feature, thus all within the scope of the present invention or the change that is equal in the scope of the invention all be included in the invention.

Embodiment 1:

Being prepared as follows CrMnTi is Pinion Steel:

(1) refining just: get the raw materials ready by following proportioning: molten iron (68～72t)+steel scrap (6～7t), add hot metal charging behind the steel scrap earlier; Raw material sent into just smelt under 1660 ℃ in the furnace, the content of regulating C during smelting endpoint is 0.06%, adopts slide plate pushing off the slag tapping to realize slag free tapping, and tapping process adopts strong deoxidation to combine with pre-deoxidation;

(2) refining: surplus the sending into respectively in the ladle refining furnace (LF stove) that is numbered D1801544, D1801543, D1801542, D1801541, D1801540 of watering that produces in the step (1) treated in the purified molten steel, carry out the reheat refining, add 150Kg reductor (AD powder: Al:18～23%, Al2O3:55～70%, MgO:＜3%, SiO2:＜8%, H2O:＜0.5%, S:＜0.05%, P:＜0.05%), make white slag fast, control slag basicity is 2.5, sulphur content is 0.026%, and refining time is 36 minutes;

(3) feed silicon-calcium wire: with the speed feeding silicon-calcium wire (Φ 13mm) of 4m/s, soft blow is 15 minutes then in molten steel, and the control sulphur content is 0.022% when leaving from station;

(4) continuous pouring: under 25 ℃ low overheat environment, technologies such as pulling rate 1.25m/min, employing liquid level are controlled automatically, crystallizer induction stirring, use big bag long nozzle (+argon envelope), submerged nozzle, middle covering agent (special-purpose insulating covering agent+carbonization rice husk), crystallizer protecting residues etc. carry out the full guard cast to molten steel, obtain qualified continuously cast bloom; (please further replenishing the description of improving this step);

(5) rolling: after continuously cast bloom is heated to 1180 ℃ it is rolled, wherein, start rolling temperature is 1060 ℃, and finishing temperature is 910 ℃;

(6) aftertreatment: for the blank of specification≤60mm, adopt the bar stacking slow cooling, slow cooling speed is 1.7 ℃/min; For the blank of specification＞60mm, adopt the slow cooling box slow cooling, slow cooling speed is 1.0 ℃/min, obtains finished product.

Composition to finished product detects, and detected result is as shown in table 1:

Table 1:

Performance test

1, grain fineness number test

Test by GB/T 6394-2002 metal mean grain size assay method, at 900 ℃, quench behind the insulation 60min, the result is as shown in table 2 for the test autstenitic grain size.

2, through hardening value test

Hardening capacity jominy end quench test method by GB/T 225-2006 steel is tested, normalizing behind insulation 35mi under 910 ℃; 880 ℃ are quenched behind the insulation 60min down, and test result is as shown in table 2.

3, non-metallic inclusion test

Test by the micro-assessment method of GB/T 10561-2005 nonmetallic inclusionsin steel, test result is as shown in table 2.

4, hardness test

By GB/T 231.1-2002 metal static hardness test first part: test method is tested, and test result is as shown in table 2.

5, banded rank test

Microstructure assessment method by GB/T 13299 steel is tested, and test result is as shown in table 2.

Table 2:

In sum, the CrMnTi that utilizes the present invention to make is that Pinion Steel has that hardening capacity is stable, mechanical property is good, the easy characteristics of processing and long service life, is ideal Pinion Steel material.

Claims (2)

1. a CrMnTi is a Pinion Steel, it is characterized in that, contain following component by weight percentage: 0.16%～0.23% C, 0.20%～0.37% Si, 0.80%～1.25% Mn, 1.00%～1.45% Cr, 0.015%～0.035% S, 0～0.035% P, 0.01%～0.02% V, 0.04%～0.10% Ti, 0.015%～0.035% Al, 0～0.25% Ni, 0～0.20% Cu, 0～0.04% Mo and the Fe and the impurity of surplus.

One kind to process the described CrMnTi of claim 1 be the complete processing of Pinion Steel, it is characterized in that, may further comprise the steps:

(1) refining just: get the raw materials ready by the described proportioning of claim 1, raw material sent into just under 1640～1670 ℃, smelt in the furnace, the content of regulating C during smelting endpoint is 0.06%～0.10%, adopt slide plate pushing off the slag tapping to realize slag free tapping, tapping process adopts strong deoxidation to combine with pre-deoxidation;

(2) refining: surplus the sending in the ladle refining furnace (LF stove) of watering that produces in the step (1) treated to carry out the reheat refining, killing in the purified molten steel, make white slag fast, control slag basicity is 2.5～3.5, and sulphur content is 0.02%～0.035%, and refining time is no less than 36 minutes;

(3) feed silicon-calcium wire: with the speed feeding silicon-calcium wire (Φ 13mm) of 2～5m/s, soft blow is more than 10 minutes then in molten steel, and the control sulphur content is 0.015%～0.035% when leaving from station;

(4) continuous pouring: under 15～30 ℃ low overheat environment, adopt technologies such as the permanent pulling rate of constant temperature, liquid level are controlled automatically, crystallizer induction stirring, use big bag long nozzle (+argon envelope), submerged nozzle, middle covering agent (special-purpose insulating covering agent+carbonization rice husk), crystallizer protecting residues etc. carry out the full guard cast to molten steel, obtain qualified continuously cast bloom;

(5) rolling: after continuously cast bloom is heated to 1130～1210 ℃ it is rolled, wherein, start rolling temperature is 1040～1100 ℃, and finishing temperature is 850～950 ℃;

(6) aftertreatment: for the blank of specification≤60mm, adopt the bar stacking slow cooling, slow cooling speed is 1.2～1.8 ℃/min; For the blank of specification＞60mm, adopt the slow cooling box slow cooling, slow cooling speed is 0.6～1.2 ℃/min, obtains finished product.