CN1706979A

CN1706979A - Cast steel for bearing parts in mechanical lifting system and its making process

Info

Publication number: CN1706979A
Application number: CN 200410046228
Authority: CN
Inventors: 赵旭平; 刘洪泽; 尹永晶; 陈彦平; 赵治洲; 周国星; 刘国友; 王芬兰
Original assignee: Sinopec Henan Petroleum Exploration Bureau Nanyang Petroleum Machinery Factory
Current assignee: Sinopec Henan Petroleum Exploration Bureau Nanyang Petroleum Machinery Factory
Priority date: 2004-06-07
Filing date: 2004-06-07
Publication date: 2005-12-14
Anticipated expiration: 2024-06-07
Also published as: CN100359036C

Abstract

The present invention relates to one kind of cast steel for bearing parts in mechanical lifting system and its making process. The cast steel of Cr-Ni-Mo line consists of C 0.15-0.30 wt%, Mn 0.60-1.10 wt%, Si 0.3-0.8 wt%, Ni 0.4-1.1 wt%, Cr 0.4-1.1 wt%, Mo 0.15-0.40 wt%, S less than 0.025 wt%, P less than 0.025 wt%, and residual elements including Cu, W and V less than 0.60 wt%. The making process of the cast steel includes the following technological steps: making steel in MF furnace or electric arc furnace; casting in sand mold with equivalent circular kiel test rod; normalizing, quenching and tempering of both cast part and test rod in the same furnace; and non-destructive detection of the cast part.

Description

Mechanical means lifting system load bearing element cast steel and manufacture method thereof

Technical field

The present invention relates to a kind of mechanical means lifting system load bearing element with cast steel and manufacture method thereof, be specially adapted to petroleum machinery equipment lifting system bearing part cast steel material.

Background technology

Requirements such as crucial bearing part, particularly petroleum machinery lift technique bearing part such as coupler body, hook tube, suspension ring, elevator have higher comprehensive mechanical performance in the mechanical means lifting system at present.(the petroleum industry press distribution of the main lift technique SY/T5208-2000 of petroleum well workover standard, calendar year 2001s 12 publication), the explanations such as (distribution of petroleum industry press were published in 1992 9) of elevator SY/T5041-92 standard is used for making casting coupler body, hook tube and elevator at present, the suspension ring material mainly is ZG34Cr2Ni2Mo, ZG35CrMo." casting handbook cast steel. the 2nd edition. Chinese China Machine Press 2002.8 has put down in writing the mechanical property (seeing the following form) of these two kinds of materials, these two kinds of materials are because carbon content is higher, toughness index is low, and ZG35CrMo intensity is also on the low side, and the casting dimension of producing is big, and weight is also big, though ZG34Cr2Ni2Mo intensity height, but except toughness was not high, because it is many to contain noble elements such as Cr, Ni, cost was than higher.These two kinds of materials all can not satisfy low temperature impact properties Akv 〉=42 J (20 ℃) requirement that API API Spec 8C standard (version in 1997) proposes foundry goods in addition.Along with the integrating with of world market, research meets international standard, it is very necessary with cast steel material to obtain the lift technique load bearing element that meets the international Valuation Standard of API.

ZG35CrMo, ZG34Cr2Ni2Mo main Mechanical

Material	????σs≥	????Akv(J)≥
Material	????σs≥	????Akv(J)≥	????ZG35CrMo	????540	32 (normal temperature)
????ZG34Cr2Ni2Mo	????700	32 (normal temperature)	????ZG35CrMo	????540	32 (normal temperature)

Summary of the invention

The problem that the present invention need solve is to propose a kind of mechanical means lifting system load bearing element high strength, high tenacity cast steel novel material and manufacture method thereof, this cast steel material can satisfy low temperature impact properties Akv 〉=42J (20 ℃) requirement that U.S. API Spec 8C standard proposes foundry goods, and problems such as solution now uses the cast steel material toughness index low, and cost is higher.

The object of the present invention is achieved like this:

Cast steel material of the present invention adopts low middle carbon Cr-Ni-Mo to be Chemical Composition such as following table:

Chemical Composition (massfraction, %)

????C	????Mn	????Si	????Ni	????Cr	????Mo	????S	????P	Residual element
								Residual element				????Cu	????W	????V	Total amount
								??0.15 ??～ ??0.30	????0.60 ????～ ????1.10	????0.3 ????～ ????0.8	????0.4 ????～ ????1.1	????Cu	????W	????V	Total amount	????0.4 ????～ ????1.1	????0.15 ????～ ????0.40	????≤ ????0.035	????≤ ????0.035	????≤ ????0.50	???≤ ???0.10	???≤ ???0.03	??≤ ??0.60

The processing step manufacturing in the following order of above-mentioned cast steel material:

1, smelting technology: adopt intermediate frequency furnace or electric-arc furnace steelmaking, strict control Chemical Composition.

2, casting technique: equivalent circular Kiel coupon is adopted in sand mold casting, mechanical property coupon.

3, thermal treatment process: adopt normalizing+double quenching and tempering,

Normalizing: 880～920 ℃ of furnace temperature are incubated 160～240 minutes, air cooling.

Double quenching: 860～900 ℃ of furnace temperature, be incubated 160～240 minutes, water-cooled is oil cooling after 30～60 seconds.

Tempering: 600～640 ℃ of furnace temperature are incubated 240～320 minutes, air cooling.

4, non-destructive test(ing)(NDT): carry out the non-destructive test(ing)(NDT) of foundry goods ray or carry out the casting ultrasonic non-destructive test(ing)(NDT) or carry out the non-destructive test(ing)(NDT) of foundry goods magnetic according to standard GB/T 9444 according to standard GB/T 7233 according to standard GB/T 5677.

Experiment condition and method by national Specification are tested test result to the mechanical property coupon: be organized as tempered sorbite, and hardness HB280-320, σ s 〉=655MPa, σ b 〉=795MPa, δ 5 〉=15%, φ 〉=40%, Akv 〉=42J (20 ℃).

Beneficial effect of the present invention is:

1, low-temperature impact toughness height: adopt low middle carbon Cr-Ni-Mo steel, can guarantee hardening capacity and intensity index, can guarantee toughness index because its carbon content is low again.

2, intensity height: adopt the double quenching technology, both guaranteed that hardening capacity was higher than common oil quenching, can reduce distortion and cracking again.

3, be suitable for massive casting: the medium-and-large-sized foundry goods of prior art is because cold etc. the reason of material chemical composition and thermal treatment process tempering oil, causes that foundry goods through hardening layer is shallow, intensity is low, poor toughness, causes casting weight big.And the combination of novel material Chemical Composition of the present invention and thermal treatment process, make hardening capacity increase, intensity and toughness index rational Match are satisfying on the basis of mechanical property, reduced the weight of foundry goods effectively, and increased the safe reliability of foundry goods and the adaptability of environment.

The invention will be further described below in conjunction with embodiment.

Embodiment

Repairing equipment lifting system bearing part elevator with the oil brill is example with cast steel and manufacture method thereof:

Its Chemical Composition sees the following form:

Chemical Composition (massfraction, %)

????C	????Mn	????Si	????Ni	????Cr	????Mo	????S	????P	Residual element
								Residual element				????Cu	????W	????V	Total amount
								??0.24～ ??0.30	??0.70～ ??1.00	????0.5～ ????0.8	????0.5～ ????0.8	????Cu	????W	????V	Total amount	?????0.5～ ?????0.8	????0.15～ ????0.30	???≤ ???0.025	???≤ ???0.025	????≤ ????0.50	????≤ ????0.10	????≤ ????0.03	????≤ ????0.60

The processing step manufacturing in the following order of this cast steel material:

1, smelting technology: adopt intermediate frequency furnace, select the electrolytic nickel of Ni 〉=99.9% for use, make steel by the Chemical Composition requirement.

2, casting technique: sand mold casting, ceramic network is filtered during casting, and the mechanical property coupon adopts equivalent circular Kiel coupon.

3, thermal treatment process: foundry goods and coupon are carried out with stove normalizing+double quenching+temper;

The car type furnace normalizing: 900 ± 10 ℃ of furnace temperature are incubated 160～200 minutes, air cooling;

The car type furnace double quenching: 880 ± 10 ℃ of furnace temperature, be incubated 160～220 minutes, water-cooled is oil cooling after 30～60 seconds;

The tempering of whirlwind tempering stove: 620 ± 10 ℃ of furnace temperature are incubated 240～280 minutes, air cooling;

4, by the requirement of GB/T5677 radiographic test steel casting is carried out the ray non-destructive test(ing)(NDT).

Empirical tests: material of the present invention has high strength, high tenacity, is specially adapted to product application such as elevator, hook block, and product weight is compared than ZG35CrMo material elevator and alleviated about 10%.

Claims

1, a kind of mechanical means lifting system load bearing element cast steel, adopting low middle carbon Cr-Ni-Mo is to it is characterized in that: Chemical Composition (massfraction, %) content C=0.15～0.30, Mn=0.60～1.10, Si=0.3～0.8, Ni=0.4～1.1, Cr=0.4～1.1, Mo=0.15～0.40, S≤0.035, P≤0.035, residual element Cu≤0.50, W≤0.10, V≤0.03, residual element total amount≤0.60.

2, be used to make the method for the cast steel of claim 1, comprise the processing step of following order:

1. smelting technology: adopt intermediate frequency furnace or electric arc furnace to make steel by the Chemical Composition requirement;

2. casting technique: equivalent circular Kiel coupon is adopted in sand mold casting, mechanical property coupon;

3. thermal treatment process: adopt foundry goods and coupon are carried out with stove normalizing+double quenching+temper;

Normalizing: 880～920 ℃ of furnace temperature are incubated 160～240 minutes, air cooling;

Double quenching: 860～900 ℃ of furnace temperature, be incubated 160～240 minutes, water-cooled is oil cooling after 30～60 seconds;

4. steel casting is adopted ray non-destructive test(ing)(NDT) or ultrasonic flaw detection or magnetic non-destructive test(ing)(NDT).

3, mechanical means lifting system load bearing element cast steel according to claim 1 is characterized in that: described Chemical Composition content (massfraction, %) in C=0.24～0.30, Mn=0.70～1.00, Si=0.5～0.8, Ni=0.5～0.8, Cr=0.5～0.8, Mo=0.15～0.30.

4, as manufacturing steel-casting method as described in the claim 2, it is characterized in that: in the described processing step:

1. smelting technology: adopt intermediate frequency furnace, select the electrolytic nickel of Ni 〉=99.9% for use;

2. casting technique: ceramic network is filtered during casting;

3. thermal treatment process:

The car type furnace normalizing: 900 ± 10 ℃ of furnace temperature are incubated 160～200 minutes;

The car type furnace double quenching: 880 ± 10 ℃ of furnace temperature are incubated 160～220 minutes;

The tempering of whirlwind tempering stove: 620 ± 10 ℃ of furnace temperature are incubated 240～280 minutes;

4. steel casting is carried out the ray non-destructive test(ing)(NDT).