CN1039835C

CN1039835C - Non-hardened and non-tempered alloy structure steel and making process thereof

Info

Publication number: CN1039835C
Application number: CN95111888A
Authority: CN
Inventors: 张玉田
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-07-20
Filing date: 1995-07-20
Publication date: 1998-09-16
Anticipated expiration: 2015-07-20
Also published as: CN1127798A

Abstract

The present invention relates to non-tempered alloy structure steel and a manufacture process thereof. Used for the manufacture of various sucker rods and mechanical parts, the non-tempered alloy structure steel has the chemical components in the following proportions (according to weight percentages) of 0.27% to 0.35% of C, 0.90% to 1.20% of Si, 0.20% to 0.50% of Mn, 0.10% to 0.20% of V, P and S respectively of not more than 0.035%, Cr, Ni and Cu respectively of not more than 0.03%, and the rest percentage of Fe. The sucker rods made of the alloy structure steel and by the manufacture process have the advantages of homogeneous metallographic structure, stable performance, high tenacity, high intensity, simple production process, long service life, etc., and without a heat treatment process which is needed by the sucker rods made by tempered steel, have the cost RMB900 yuan per ton less than that made of the tempered steel.

Description

Non-hardened and non-tempered alloy structure steel and manufacturing process

The invention belongs to steel alloy and manufacturing process field thereof, particularly a kind of structural alloy steel 30SiMnV and manufacturing process thereof are used to make various D grade pumping rods or mechanical part.

At present, petroleum drilling adopts high-quality alloy steels such as 20CrMo, or 35CrMo usually with high-strength pumping rod, through quenching---and the modifier treatment and the machining process of high tempering are made.For reducing production costs, Chinese patent 90104471.7 discloses a kind of steel for sucker rod and technology, and this method is to use 40Mn ₂Produce high-strength pumping rod after the modifier treatment of Nb steel.But 40Mn ₂Equally to consume a large amount of energy with hardening and tempering process such as tempering in the past in the Nb modifier treatment process.

At present, for solving the big problem of power consumption, non-hardened and tempered steel is energy-conservation direction.And also do not have sophisticated steel grade both at home and abroad, all in conceptual phase.Chinese patent 92102405.3 discloses a kind of high-strength non-hardened and non-tempered steel for pumping rod, and this steel saves thermal treatment and reduces cost.Its chemical ingredients: C 0.10-0.20%; Mn 2.00-3.00%; Si 0.40-1.40%; Cr 0.40-1.10%; V 0.05-0.20%; Mn 0.15-0.35%.But this Carbon Content Of Steel is low, hardness is big, be easy to generate crackle when processing difficulties, forging cooling.In the world, the non-hardened and tempered steel electricity is in the development stage, does not formally list the structural alloy steel standard in.

The objective of the invention is in order to solve the problem that speed exists, provide a kind of metallographic structure evenly, stable performance, long service life, and can save the structural alloy steel that the thermal treatment process sucker rod is used.

The chemical ingredients of non-hardened and non-tempered alloy structure steel of the present invention is (by weight percentage)

C?0.27-0.35、Si 0.90-1.20、Mn?1.20-1.5、

V?0.10-0.20、P、S≤0.035、Cr、Ni、Cu≤0.03、

Al 0.03-0.05, all the other are iron Fe.

Make the processing step of above-mentioned non-hardened and non-tempered alloy structure steel: be to prepare burden by the above-mentioned chemical ingredients that provides, on electric arc furnace, smelt then, it is characterized in that: in smelting procedure, in coming out of the stove the forward direction molten steel, molten steel adds iron alloy Fe-V and Al, make its content be: Al0.03-0.05%, V 0.10-0.20%, every stove molten steel is cast steel ingot, intact back is adopted first cogging to reroll and is made the steel secondary processes, be that ingot casting adds and is rolled into steel billet, cooling back reheat mill product steel, maximum heating temperature is 1180 ℃, finishing temperature 〉=900 ℃ of control stocking, and finished steel is evenly cooling on cold bed, 70 ℃/minute of control stocking speed of cooling, by recovering recrystallize, obtain that (C N) is the steel of the thinning microstructure of core with V.

Adopt said ratio and technology, provide a kind of type material for making sucker rod, we in order fully to set forth technical scheme of the present invention, now are described as follows its called after: 30SiMnV with the reason of each composition function and range of choice and the formulation of manufacturing process measure:

Carbon (C), adjust ferrite in the steel: strain light body=3: 7 ratios, the intensity and the plasticity of assurance steel, range of choice is C 0.27-0.35%.

Silicon (Si) manganese (Mn) plays intensity, particularly reinforced ferrite intensity that the solution strengthening effect improves steel, and range of choice is Si 0.90-1.20%; Mn 1.20-1.50%.

Alum (V) plays dispersion-strengthened action: by generating third phase particle V (C.N), prevent the generation of slippage, strengthen the intensity of steel; Another effect: V, N crystal grain thinning degree, the intensity and the toughness of increase steel prevent to heat the grain coarsening performance depreciation, and range of choice is V 0.10-0.20%.

Sulphur (S) and phosphorus (P) they are harmful element, be controlled at≤0.035%.

Copper (Cu), chromium (Cr) and nickel (Ni) they are impurity, and content is controlled at≤and below 0.030%, all the other are iron Fe.

Why non-hardened and non-tempered alloy structure steel of the present invention can reach the low and low double effects of tooling cost of material cost, is characterized in that the chemical ingredients proportioning is based on C, belongs to medium carbon steel, and the outstanding feature in the technology is:

1. the Al amount is inserted in the control deoxidation in the smelting procedure, and it is effective simultaneously with V to make in the steel Al amount reach 0.03-0.05%, the grain fineness number of dual control steel, and V controls prior austenite grain size, and Al controls inherent grain size, by the grain fineness number refinement, can improve the intensity and the toughness of steel again.

2. adopt first cogging to reroll into the steel secondary processes.Finishing temperature 〉=900 ℃ of control stocking are by recovering recrystallize, and obtaining with V (C.N) be the thinning microstructure of core, the performance of assurance steel.

3. control stocking speed of cooling is 70 ℃/minute, obtains thinning microstructure, improves intensity and toughness.

By the combination of above-mentioned prescription and technology, make the structural alloy steel of this invention satisfy the D level and take out its performance of national standard of bar and reach: tensile strength sigma _b〉=800N/mm ², yield strength σ.〉=620N/mm ², unit elongation δ ₅〉=10%, relative reduction in area ψ 〉=45%, ballistic work AKu 〉=60.8J/cm ², see table 1D grade pumping rod performance requriements for details.

Non-modified and golden structure iron of the present invention has been produced 2 kinds of products, and a kind of is the D grade pumping rod, has made fatigue experiment 54Kg/mm in the laboratory ²Stress condition reaches 2 * 10 ⁶Inferior, the D grade pumping rod of making was gone into the well experiment respectively for 2 years, did not find any problem so far; Plant in addition is that ton product has been gone into the well experiment for a year and a half surplus 25 3 specifications of polished rod Φ 32, Φ 28, Φ, 29 stoves 340 of oil recovery usefulness, so far do not find any problem, it is simple to make sucker rod technology with non-hardened and tempered steel in a word, save thermal treatment and reduced by 900 yuan/t of cost, and the sucker rod long service life, be to innovate on a kind of sucker rod production technology.

The embodiment of the invention: chemical ingredients of the present invention (by weight percentage) is

C?0.27-0.35、Si 0.90-1.20、Mn?1.20-1.5、

V?0.10-0.20、P、S≤0.035、Cr、Ni、Cu≤0.03、

AL 0.03-0.05, all the other are iron Fe.

Carry out actual batching by the chemical ingredients that this proportioning provides, on 70.5 tons of electric arc furnace, smelt then, in the forward direction molten steel of coming out of the stove, add iron alloy Fe-V and aluminium Al, make that V content reaches 0.10-0.20% in the steel, the Al amount reaches 0.03-0.05%, every stove molten steel is cast steel ingot, each heavy 600Kg, again steel ingot is heated to 1220 ℃ after, cogging becomes Φ 70-90 circle base on 650 milling trains, be cooled to 10 ℃, and then be heated to 1180 ℃, rolling on the 400-250 milling train, finishing temperature 〉=900 ℃, 70 ℃/minute of stocking speed of cooling promptly roll into Φ 32, Φ 28, Φ 25 round steel are processed into sucker rod then.

D grade pumping rod performance requriements tensile strength sigma _b〉=794N/mm ², yield strength σ ₃〉=620/mm ², unit elongation δ ₅〉=10%, relative reduction in area 〉=45%, ballistic work AK _u〉=60.8J/cm ²

Claims

1, a kind of non-hardened and non-tempered alloy structure steel is characterized in that chemical ingredients (by weight percentage) is

C 0.27-0.35、Si 0.90-1.20、Mn?1.20-1.5、

V 0.10-0.20、P、S≤0.035、?Cr、Ni、Cu≤0.03、

Al 0.03-0.05, all the other are Fe.

2, a kind of technology of making non-hardened and non-tempered alloy structure steel as claimed in claim 1, its processing step: be to prepare burden by the above-mentioned chemical ingredients that provides, on electric arc furnace, smelt then, it is characterized in that: in smelting procedure, in coming out of the stove the forward direction molten steel, molten steel adds iron alloy Fe-V and Al, make its content be: Al 0.03～0.05%, V 0.10-0.20%, every stove molten steel is cast steel ingot, intact back adopts first cogging to reroll into the steel secondary processes, and promptly ingot casting adds and is rolled into steel billet, cooling back reheat mill product steel, maximum heating temperature is 1180 ℃, finishing temperature 〉=900 ℃ of control stocking, finished steel is evenly cooling on cold bed, and 70 ℃/minute of control stocking speed of cooling are by recovering recrystallize, obtain that (C N) is the steel of the thinning microstructure of core with V.