CN104152807B

CN104152807B - The preparation method of high-capacity light gas cylinder

Info

Publication number: CN104152807B
Application number: CN201410376301.4A
Authority: CN
Inventors: 李连贵; 雷丙旺; 胡永平; 周仲成; 李宝臣; 石宝凤; 白箴; 任胜利; 刘海江
Original assignee: Inner Mongolia North Heavy Industries Group Co Ltd
Current assignee: Inner Mongolia North Heavy Industries Group Co Ltd
Priority date: 2014-08-03
Filing date: 2014-08-03
Publication date: 2016-03-16
Anticipated expiration: 2034-08-03
Also published as: CN104152807A

Abstract

The present invention relates to a kind of preparation method of high-capacity light gas cylinder, belong to pressurized vessel field.The present invention adopts electrosmelting, vacuum refinement, esr process refining to obtain 38CrNi3MoV steel ingot; Through 1250 DEG C ~ 1300 DEG C diffusion annealings that homogenize, vertical extruder is utilized to be squeezed into steel pipe blank, steel pipe blank carries out slow cooling to 650 ± 10 DEG C isothermal annealing after austenitizing, through bore hole, turning machining, heat treatment quenching and tempering, make operating pressure≤40MPa, the gas cylinder used under corrosive environment of sea water.Gas cylinder prepared by the present invention, have higher intensity and impelling strength level after thermal treatment, Rp0.2 >=980MPa, Rm >=1130MPa, Z >=50% ,-20 DEG C of Akv >=70J ,-50 DEG C of Akv >=65J, over-all properties meets the technical requirements of light high pressure gas cylinder completely.

Description

The preparation method of high-capacity light gas cylinder

Technical field

The present invention relates to a kind of preparation method of high-capacity light gas cylinder, belong to pressurized vessel field.

Background technology

At present, the gas cylinder that some particular surroundingss are used, smelting adopts electric arc furnace to add external refining and through vacuum refinement process, or oxygen coverter adds external refining and through vacuum refinement process, steel pipe forming generally adopts hot rolling (expansion) or hot rolling (expansion)+seamless cold method to manufacture, maximum working pressure (MWP)≤30MPa.And certain user needs the major diameter light high pressure gas cylinder that uses under more exacting terms, operating pressure≤40MPa, uses under corrosive environment of sea water.According to existing technique, its performance can not meet the technical requirements of this major diameter light high pressure gas cylinder.

Summary of the invention

The object of the present invention is to provide that a kind of material purity is high, geometric accuracy is high, comprehensive mechanical property is high, the preparation method of the high-capacity light gas cylinder used under can meeting particular surroundings.

Technical solution

The present invention includes following method steps:

1, grade of steel and chemical Composition Control is selected

Grade of steel is selected to be 38CrNi3MoV steel, its chemical Composition Control comprises by quality amount percentages: C-0.33 ~ 0.40%, Mn-0.27 ~ 0.47%, Si-0.17 ~ 0.37%, Cr-1.20 ~ 1.45%, Ni-3.00 ~ 3.50%, Mo-0.35 ~ 0.45%, V-0.10 ~ 0.15%, W≤0.20%, Cu≤0.20%, Ti≤0.020%.

2, deoxidation

1) vacuum carbon deoxidization: first liquid steel temperature is heated to 1680 ~ 1700 DEG C before refining, subsequently under 67MPa vacuum tightness, adopt large Argon intensity method, Argon intensity control is 21 ~ 23Nm ³/ h, carries out the vacuum carbon deoxidization technique deoxidation of 15 ~ 20 minutes; Reduce the oxide inclusion that bulk deoxidation generates.

2) composite deoxidant deoxidation: add 0.3 ~ 0.5kg Si-Al-Ca-Ba composite deoxidant in steel per ton under vacuum conditions after vacuum carbon deoxidization terminates and carry out deoxidation.

3) diffusive deoxidation: add calcium carbide, ferrosilicon powder or brick powder after forming white slag in 10 ~ 20 points of clockwise molten liquid steels and carry out diffusive deoxidation.In steel per ton, add-on is: calcium carbide 0.8 ~ 0.9kg, ferrosilicon powder 0.3 ~ 0.5kg, aluminium powder 0.4 ~ 0.5kg, and by entire oxygen content in the steel content control≤15PPm, all kinds of by GB10561 grading is respectively inclusion sum≤2.0 grade;

3, esr

Step 2) electrode billet that obtains carries out esr.Reflow process adopts low current high-voltage, and electric current is 14000A ~ 15000A, and voltage is 90V ~ 93V, forms shallow pool.

4, enclosed jumping-up+reverse extrusion punching

The ESR ingot that step 3) obtains is heated to 1270-1290 DEG C in chamber-type heating furnace, removes surface of steel ingot oxide skin, carries out enclosed jumping-up after sprayed glass lubricant at base press, upset ratio 1.3 ~ 2.0, reverse extrusion punching, piercing ratio reaches 1.2 ~ 1.8, makes hollow blank;

5, extrusion molding

The blank that step 4) obtains reheats to 1270-1290 DEG C, homogenize diffusion annealing after 20 ~ 30 hours, removes hollow billet surface scale, after sprayed glass lubricant, on extrusion machine, hollow billet is squeezed into pipe, extrusion speed 30-40mm/s, extrusion ratio >=6;

6, anneal

Slow cooling to 650 ± 10 DEG C isothermal annealing after the pipe austenitizing that step 5) obtains, annealing time 40-60 hour, is balanced the perlite+ferritic structure of state;

7, machining

The steel pipe blank that step 6) obtains, through bore hole, turning machining, obtains outer diameter tolerance 230-600mm ± 0.5%; The steel pipe of wall thickness 12 ~ 30mm, wall thickness tolerance 0 ~+0.3mm;

8, thermal treatment

The steel pipe that step 7) obtains according to gas cylinder manufacturing process spinning closing-in, then through Tempering and Quenching.

the effect of invention

1) material adopts and does with the 38CrNi3MoV steel of electrosmelting, the refining of vacuum carbon deoxidization technology, esr.There is high purity, low harmful element content and gas content.

2) steel ingot after esr is isothermal annealed processes base after heating, extrusion machine base, the diffusion annealing that homogenizes, vertical extrusion process extruding, austenitizing, effectively can improve density, the homogeneity of steel, improve anisotropy, remarkable crystal grain thinning.

3) pipe is through the machining of turning, boring endoporus, has good geometric accuracy and surface quality.

4) have higher intensity and impelling strength level after thermal treatment, Rp0.2 >=980MPa, Rm >=1130MPa, Z >=50% ,-20 DEG C of Akv >=70J ,-50 DEG C of Akv >=65J, obtained gas cylinder over-all properties meets the technical requirements of light high pressure gas cylinder completely.

Accompanying drawing explanation

fig. 1 is present invention process schema.

Embodiment

1) electrosmelting, vacuum carbon deoxidization refining, esr is adopted to obtain 38CrNi3MoV steel ingot; Its chemical composition is in table 1:

2) 15000t extrusion machine just base is adopted after Heating Steel Ingots, then through 1250 DEG C ~ 1300 DEG C diffusion annealings 20 ~ 30 hours that homogenize, then be squeezed into steel pipe blank through 36000t vertical extruder;

3) steel pipe blank carries out slow cooling to 650 ± 10 DEG C isothermal annealing after austenitizing, and annealing time 40-60 hour, is balanced the perlite+ferritic structure of state;

4) the steel pipe blank of step 3) is through bore hole, turning machining, obtains outer diameter tolerance ± 0.5%; The steel pipe of wall thickness 12 ~ 30mm, wall thickness tolerance 0 ~+0.3mm;

5) step 4) obtains steel pipe according to gas cylinder manufacturing process spinning closing-in, then through modified heat place.Gas cylinder prepared by the present invention, has higher intensity and impelling strength level, Rp0.2 >=980MPa, Rm >=1130MPa after thermal treatment, Z >=50% ,-20 DEG C of Akv >=70J ,-50 DEG C of Akv >=65J, over-all properties meets the technical requirements of light high pressure gas cylinder completely.Grain fineness number is narrower than 7 grades.

2012, a collection of steel pipe meeting this kind of gas cylinder technical requirements was made by the north, Inner Mongol heavy industry group company, through spinning closing-in, has made gas cylinder.After gas cylinder finished product is heat-treated, detect the every mechanical performance index of gas cylinder in table 2, meet design requirements.

Claims

1. the preparation method of high-capacity light gas cylinder, is characterized in that, preparation method comprises the steps:

1) grade of steel and chemical Composition Control is selected

Grade of steel is selected to be 38CrNi3MoV steel, its main chemical compositions controls to comprise by quality amount percentages: C-0.33 ~ 0.40%, Mn-0.27 ~ 0.47%, Si-0.17 ~ 0.37%, Cr-1.20 ~ 1.45%, Ni-3.00 ~ 3.50%, Mo-0.35 ~ 0.45%, V-0.10 ~ 0.15%, W≤0.20%, Cu≤0.20%, Ti≤0.020%;

2) deoxidation

A) vacuum carbon deoxidization: first liquid steel temperature is heated to 1680 ~ 1700 DEG C before refining, subsequently under 67MPa vacuum tightness, adopt large Argon intensity method, Argon intensity control is 21 ~ 23Nm ³/ h, carries out the vacuum carbon deoxidization technique deoxidation of 15 ~ 20 minutes;

B) composite deoxidant deoxidation: add 0.3 ~ 0.5kg Si-Al-Ca-Ba composite deoxidant in steel per ton under vacuum conditions after vacuum carbon deoxidization terminates and carry out deoxidation;

C) diffusive deoxidation: add calcium carbide, ferrosilicon powder or aluminium powder after forming white slag in 10 ~ 20 points of clockwise molten liquid steels and carry out diffusive deoxidation; In steel per ton, add-on is: calcium carbide 0.8 ~ 0.9kg, ferrosilicon powder 0.3 ~ 0.5kg, aluminium powder 0.4 ~ 0.5kg, and by entire oxygen content in the steel content control≤15PPm, all kinds of by GB10561 grading is respectively inclusion sum≤2.0 grade;

3) esr

Step 2) electrode billet that obtains carries out esr; Reflow process adopts low current high-voltage, and electric current is 14000A ~ 15000A, and voltage is 90V ~ 93V, forms shallow pool;

4) enclosed jumping-up+reverse extrusion punching

5) extrusion molding

6) anneal

7) machining

8) thermal treatment

The steel pipe that step 7) obtains according to gas cylinder manufacturing process spinning closing-in, then through Tempering and Quenching, makes operating pressure≤40MPa, the gas cylinder used under corrosive environment of sea water; Gas cylinder mechanical property: Rp0.2 >=980MPa, Rm >=1130MPa, Z >=50% ,-20 DEG C of Akv >=70J ,-50 DEG C of Akv >=65J.