CN102329942A - Thermal treatment process for directly-connected sleeve - Google Patents

Abstract

The invention discloses a thermal treatment process for a directly-connected sleeve. The process comprises the following steps of: a, feeding a sleeve with thickened end into a quenching furnace, and heating the whole sleeve to the temperature of between 950 and 1,000 DEG C; b, putting the heated sleeve on a rotary quenching frame, and performing integral water quenching on the sleeve at the temperature of 900 DEG C, wherein the temperature of cooling water is 25 to 30 DEG C; and c, delivering the quenched sleeve to a tempering furnace, heating the sleeve to the temperature of between 600 and 650 DEG C, and performing tempering treatment and air cooling. By the thermal treatment process, the sleeve body and the thickened end have different cooling velocities after being quenched, the thickened end of the sleeve with thickness of more than 25 millimeters is totally quenched, the thickened end and the sleeve body part of the sleeve have the same quenched structure and consistent mechanical properties, and the squeezing damage resistance of the produced sleeve can be over 15 percent higher than the specified value of API 5C2 standard. The process is suitable for thermal treatment of sleeves made of steel with high Mn content and a certain amount of V.

Description

A kind of direct linkage type sleeve pipe thermal treatment process

Technical field

The present invention relates to the heat treatment technics field, especially a kind of direct linkage type sleeve pipe thermal treatment process.

Background technology

The direct linkage type sleeve pipe of using always in the oil gas well mining, because pipe end section is a upset end, the difference in thickness of its thickness and body is bigger; When under equal quenching temperature and cooling conditions, heat-treating, pipe end is thick more, and then pipe end is just slow more with respect to the speed of cooling of body; The quenching hardness of pipe end is just low more, tempered like this after, the mechanical property of pipe end is in general than about the low 50MPa of body portion; When serious even more than the low 100MPa, the hardness of pipe end also is significantly less than body.Because therefore the connection each other of direct linkage type sleeve pipe, if telescopic upset end mechanical property is on the low side, will directly influence telescopic overall performance and generation safe in utilization through connecting behind the processing internal and external threads on the thickening pipe end.Because what the high-performance casing design was mainly considered is mechanical property, during thermal treatment, the C that contains in the steel, Mn are the main raws that improves hardening capacity; In order to guarantee the hardening capacity of sleeve pipe upset end, should add higher C, Mn, but because the body wall thickness is thinner; The too high body that then makes easily of hardening capacity produces hardening crack, should suitably reduce hardening capacity again for this reason, causes contradiction between the two; And in the used steel grade of existing sleeve pipe, C, Mn content are all very high, and hardening capacity is very good; But under the through hardening situation that guarantees direct linkage type sleeve pipe upset end, body then is easy to occur quenching crack.

Summary of the invention

The technical problem that the present invention will solve is: overcome the deficiency in the prior art; A kind of direct linkage type sleeve pipe thermal treatment process is provided; Make direct linkage type sleeve pipe body partly have consistent and higher mechanical property with upset end, the sleeve pipe of guaranteeing to produce is anti-to be squeezed and ruins performance greater than API 5C2 standard gauge definite value more than 15%.

The technical solution adopted for the present invention to solve the technical problems is: a kind of direct linkage type sleeve pipe thermal treatment process is applicable to the steel grade of following ingredients and weight percent is heat-treated: C:0.22～0.28; Si:0.15～0.35; Mn:1.35～1.60; Cr :≤0.15; P :≤0.02; S :≤0.01; Cu :≤0.20; Ni :≤0.20; V:0.08～0.15; Ti:0.015～0.022, surplus are iron, and this thermal treatment process has following steps:

A, the sleeve pipe that pipe end has been thickeied are sent into quenching furnance, carry out integral body and are heated to 950～1000 ℃;

B, the sleeve pipe after will heating are positioned on the spin hardening frame through raceway; When 900 ℃ of temperature, sleeve pipe is carried out whole shrend; The quenching mode is in the sleeve pipe rotation, to the cooling of internal surface of sleeve pipe water spray, the cooling of sleeve surface water curtain; The upset end part at sleeve pipe two ends increases the cooling of a cooling-water pump water spray respectively, and coolant water temperature is 25～30 ℃;

C, send the sleeve pipe after quenching to and be heated to 600～650 ℃ in the tempering stove, sleeve pipe is carried out temper, it is cold that sleeve pipe goes out the laggard line space of tempering stove.

The invention has the beneficial effects as follows: thermal treatment process according to the invention; Thermal treatment process according to the invention; Can regulate body and after quenching, have different speed of cooling with upset end; Guarantee the complete through hardening of sleeve pipe upset end of the above thickness of 25mm, make sleeve pipe upset end and body portion have identical quenching structure, under the situation that does not produce quenching crack; Can guarantee after tempered that direct linkage type sleeve pipe body partly has consistent and higher mechanical property with upset end, the sleeve pipe of guaranteeing to produce is anti-to be squeezed and ruins performance greater than API 5C2 standard gauge definite value more than 15%.The telescopic heat treatment process that the present invention is applicable to the Mn that contains higher amount and contains the steel grade making of a certain amount of V.

Embodiment

In conjunction with the preferred embodiments the present invention is further described now.

Below be example with the direct linkage type sleeve pipe of following specification, the present invention is further described.

Table 1

Specification	The upset end external diameter	The upset end internal diameter	Upset end length	The body average wall thickness
					127×9.19	140.5	100.2	125	9.3

Above-mentioned composition and the weight percent that is used to make direct linkage type telescopic steel grade is following: C:0.25; Si:0.20; Mn:1.45; Cr:0.1; P:0.01; S:0.008; Cu:0.15; Ni:0.10; V:0.11; Ti:0.02; Surplus is an iron.

The function description of principal element is following in the mentioned component:

C: be the forming element of carbide, can improve the intensity of steel, DeGrain when content is too low, but too Gao Shihui reduces the toughness of steel greatly, and might produce quenching crack;

Si: be the element that must add, but too high levels then can influence the fragility of material for the raising opourability;

Mn: be austenite former,, postpone in the high temperature cooling process austenite to the transformation of ferritic and bainite, thereby obtain more quenched martensite, raising hardening capacity through the stable austenite tissue; It is not clearly that Mn content be lower than at 1.35 o'clock to improve hardening capacity, too high levels, and then austenite is too stable, is unfavorable for obtaining quenched martensite;

V: can crystal grain thinning, form carbide, improve the toughness and the intensity of steel; When reaching a certain amount of, the effect of increase has been not clearly just, and the V price is very high, so the use of will limiting the quantity of;

Ti: can crystal grain thinning, form carbide, improve the toughness and the intensity of steel; When reaching a certain amount of, the effect of increase has been not clearly just;

At first above-mentioned steel are made into the direct linkage type sleeve pipe, and the telescopic pipe end is thickeied processing, CS is seen shown in the table 1.

The thermal treatment process step is following:

A, the sleeve pipe that pipe end has been thickeied are sent into quenching furnance, carry out integral body and are heated to 980 ℃;

B, the sleeve pipe after will heating are positioned on the spin hardening frame through raceway; When 910 ℃ of temperature, sleeve pipe is carried out whole shrend, the quenching mode is in the sleeve pipe rotation, to the cooling of internal surface of sleeve pipe water spray; The cooling of sleeve surface water curtain; Coolant water temperature is 30 ℃, simultaneously in the upset end part at sleeve pipe two ends, increases the cooling of a cooling-water pump water spray respectively; Spray flow through strengthening upset end makes the upset end of different wall have identical speed of cooling with body, to guarantee that upset end has identical quenching structure with body;

C, send the sleeve pipe after quenching to and be heated to 640 ℃ in the tempering stove, sleeve pipe is carried out temper, it is cold that sleeve pipe goes out the laggard line space of tempering stove.

Table 2

Table 2 is the temperature value selected for use in the above-mentioned thermal treatment process and the mechanical behavior value of thermal treatment rear sleeve body and upset end.

From table 2, can find out; After adopting thermal treatment of the present invention; Telescopic body and upset end all have higher mechanical mechanics property, and both performance numbers are comparatively approaching, thereby anti-the squeezing of the sleeve pipe of guaranteeing to produce ruined performance greater than API 5C2 standard gauge definite value more than 15%.

Here replenish API 5C2 standard gauge definite value.。。。。。。

The foregoing description only is explanation technical conceive of the present invention and characteristics; Its purpose is to let the personage that is familiar with this technology can understand content of the present invention and implements; Can not limit protection scope of the present invention with this; All equivalences that spirit is done according to the present invention change or modify, and all should be encompassed in protection scope of the present invention.

Claims (1)

1. a direct linkage type sleeve pipe thermal treatment process is applicable to the steel grade of following ingredients and weight percent is heat-treated: C:0.22～0.28; Si:0.15～0.35; Mn:1.35～1.60; Cr :≤0.15; P :≤0.02; S :≤0.01; Cu :≤0.20; Ni :≤0.20; V:0.08～0.15; Ti:0.015～0.022, surplus is an iron, it is characterized in that: comprise the steps:

A, the sleeve pipe that pipe end has been thickeied are sent into quenching furnance, carry out integral body and are heated to 950～1000 ℃;

B, the sleeve pipe after will heating are positioned on the spin hardening frame through raceway; When 900 ℃ of temperature, sleeve pipe is carried out whole shrend; The quenching mode is in the sleeve pipe rotation, to the cooling of internal surface of sleeve pipe water spray, the cooling of sleeve surface water curtain; The upset end part at sleeve pipe two ends increases the cooling of a cooling-water pump water spray respectively, and coolant water temperature is 25～30 ℃;

C, send the sleeve pipe after quenching to and be heated to 600～650 ℃ in the tempering stove, sleeve pipe is carried out temper, it is cold that sleeve pipe goes out the laggard line space of tempering stove.