CN101890439A - Manufacturing process of cold-drawing seamless pipe for vehicular wrapped gas bottle - Google Patents

Abstract

The invention relates to a manufacturing process of a cold-drawing seamless pipe for a vehicular wrapped gas bottle, comprising the following steps of: carrying out thermal expansion on a hot rolling raw material pipe with the nominal size of phi 273*8.2 into a thermal expansion raw material pipe with the nominal size of phi 415*7.5, and then carrying out cold drawing to form a finished specification steel pipe with the nominal size of phi 406*5.9. The invention relates to the manufacturing process of the new-specification cold-drawing seamless pipe for the vehicular wrapped gas bottle, a product having the specification of phi 406*5.9 and having the characteristics of large volume weight ratio and light weight of a single gas bottle can be produced by using a thermal expansion and cold drawing method, and the gas bottles internally contains flammable and explosive mediums, has the nominal working pressure up to 20Mpa, is in a moving state with a vehicle, and has reliable safety performance. The product of the invention is firstly and exclusively produced in China, can completely satisfy the technical requirements of users, and has excellent performance and wide market potential.

Description

The manufacturing process of cold-drawing seamless pipe for vehicular wrapped gas bottle

Technical field

The invention belongs to metallurgical technology field, relate to large-caliber thin-walled new spec seamless cold gas cylinder tube, particularly a kind of manufacturing process of cold-drawing seamless steel tube for vehicular wrapped gas cylinder.

Background technology

Automobile is in recent years for adapting to a kind of novel gas cylinder that the CNG development of automobile is developed with compressed natural gas steel inner bag hoop winding gas cylinder (hereinafter to be referred as the CNG bottle).According to national legislation, must regularly carry out safety examination to the CNG gas cylinder, the manufacturing process of solid drawn tube that therefore is used to make compressed natural gas used as vehicle fuel steel inner bag hoop winding gas cylinder is particularly important.

Limited by working condition and technical merit, present heavy caliber (＞325mm) hot finished steel pipe is difficult to thickness of steel pipe is rolled below the 6mm, also has a large-diameter and thin-wall pipe aligning difficult problem simultaneously.

Summary of the invention

The objective of the invention is to overcome the deficiencies in the prior art, provide that a kind of security performance is good, volume to weight ratio is big, the manufacturing process of the lightweight cold-drawing seamless steel tube for vehicular wrapped gas cylinder of monomer gas cylinder.

The objective of the invention is to be achieved through the following technical solutions:

A kind of manufacturing process of cold-drawing seamless steel tube for vehicular wrapped gas cylinder adopts nominal dimension Φ 273 * 8.2 hot rolling mother tubes to expand through heat and expands mother tubes to Φ 415 * 7.5 heat and be cold drawing to Φ 406 * 5.9 trimmed size steel pipes again, and concrete processing step is:

Heat expands technology: hot rolling mother tube Φ 273 * 8.2 heat expand to Φ 415 * 7.5:

(1) surfaces externally and internally quality, external diameter, the wall thickness of described specification Φ 273 * 8.2 hot rolling mother tubes of check select for use the same cross section hot-expanding pipe of wall thickness deviation below 1.0mm as mother tube;

(2) it is lubricated with graphitic lubricant heat to be expanded the mother tube inwall: graphite aqueous solution configuration requirement: 20 kilograms of graphite add 200 premium on currency;

(3) adjust the thermal expansion machine technological parameter: electric current 550～650A, voltage 450～500V, expansion speed 630mm/min;

(4) selected core print size: Φ 400mm core print surface will be cleaned out, and evenly smears graphitic lubricant;

(5) the preceding high back of the preceding blanking rack of adjustment thermal expansion machine is hanged down and is carried out the heat expansion;

(6) after the heat expansion finishes, check hot-expanding pipe surface quality, wall thickness;

(7) hot-expanding pipe is carried out interior mill, grind off the remaining graphite of steel pipe;

Cold-drawing technology: hot-expanding pipe Φ 415 * 7.5 is cold drawing to Φ 406 * 5.9:

(1) pickling: chlorohydric acid pickling, concentration 30%, 40 ℃ ± 5 ℃ of temperature, soak time 6 hours;

(2) phosphatization: General Acidity in Phosphating Solution 20～25 points, free acid 2.0～2.5 points, 60～70 ℃ of temperature, soak time 30～35 minutes;

(3) saponification: saponification liquor aliphatic acid＞50 grams per liters, free acid＜5 grams per liters, 80～85 ℃ of temperature, soak time 5 minutes;

(4) steel pipe cold-drawn: pickling, lubricated qualified steel pipe carry out draw on 400 tons of hydraulic pressure cold drawing machines, by Φ 415 * 7.5 a time draws to Φ 406 * 5.9;

(5) production tube surface quality, physical dimension, out-of-roundness, flexibility control;

(6) fished pipe check.

Advantage of the present invention and good effect are:

1, the present invention is that a kind of material is the manufacturing process of the cold-drawing seamless steel tube for vehicular wrapped gas cylinder of 30CrMo, the heat expansion adds cold-drawing method and can produce Φ 406 * 5.9 specification products, have big volume to weight ratio, monomer gas cylinder characteristics in light weight, the inflammable and explosive medium of splendid attire in the gas cylinder, nominal operating pressure can reach 20MPa, and be in the car mobile status, security performance is reliable.

2, product of the present invention is domestic exclusively production first, and function admirable satisfies technical requirements of users comprehensively, has wide market prospects.

The specific embodiment

The invention will be further described below in conjunction with specific embodiment, and following examples are descriptive, is not determinate, can not limit protection scope of the present invention with this.

A kind of manufacturing process of cold-drawing seamless steel tube for vehicular wrapped gas cylinder adopts nominal dimension Φ 273 * 8.2 hot rolling mother tubes, and material is 30CrMo, expands through heat and expands mother tubes to Φ 415 * 7.5 heat and be cold drawing to Φ 406 * 5.9 trimmed size steel pipes again.Concrete processing step is:

1, heat expands technology: hot rolling mother tube Φ 273 * 8.2 heat expand to Φ 415 * 7.5.

(1) surfaces externally and internally quality, external diameter, the wall thickness of described specification Φ 273 * 8.2 hot rolling mother tubes of check select for use the same cross section hot-expanding pipe of wall thickness deviation below 1.0mm as mother tube.

(2) heat expansion mother tube inwall is lubricated: graphite aqueous solution configuration requirement: 20 kilograms of graphite add 200 premium on currency.

(3) adjust the thermal expansion machine technological parameter: electric current 550～650A, voltage 450～500V, expansion speed 630mm/min.

(4) selected core print size: Φ 400mm core print surface will be cleaned out, and evenly smears graphitic lubricant.

(5) the preceding high back of the preceding blanking rack of adjustment thermal expansion machine is hanged down and is carried out the heat expansion.

(6) after the heat expansion finishes, check hot-expanding pipe surface quality, wall thickness.

(7) hot-expanding pipe is carried out interior mill, grind off the remaining graphite of steel pipe inwall.

2, cold-drawing technology: hot-expanding pipe Φ 415 * 7.5 is cold drawing to Φ 406 * 5.9.

(1) satisfactory heat is expanded mother tube and carry out pickling earlier: chlorohydric acid pickling, concentration 30%, 40 ℃ ± 5 ℃ of temperature, soak time 6 hours expands mother tube surfaces externally and internally oxide skin with heat and the graphite residue is cleaned.

(2) phosphatization: General Acidity in Phosphating Solution 20～25 points, free acid 2.0～2.5 points, 60～70 ℃ of temperature, soak time 30～35 minutes makes its steel pipe surfaces externally and internally form skim light green color phosphating coat.

(3) saponification: saponification liquor aliphatic acid＞50 grams per liters, free acid＜5 grams per liters, 80～85 ℃ of temperature, soak time 5 minutes.Steel tube surface forms the even saponification film of skim after the saponification.

(4) steel pipe cold-drawn: pickling, lubricated qualified steel pipe carry out draw on 400 tons of hydraulic pressure cold drawing machines, by Φ 415 * 7.5 a time draws to Φ 406 * 5.9 (trimmed size).

(5) production tube surface quality, physical dimension, out-of-roundness, flexibility control:

By external mold, the design of internal mold physical dimension are reached physical dimension coupling between the two, finally control external diameter, wall thickness, out-of-roundness, the flexibility index of steel pipe, make it meet the relevant art conditional request.

In the present embodiment, external mold physical dimension and internal mold physical dimension are conventional computational methods.

3, steel pipe check:

(1), by propping up production tube is carried out the wall thickness detection, sampling observation outer diameter of steel pipes, out-of-roundness, flexibility according to respective standard or technical protocol.These indexs all should meet the technical conditions requirement.

(2) according to GB5777-2008 " seamless steel pipe supersonic method of detection " L2 rank, by propping up steel pipe is carried out ultrasonic examination, reject defective steel pipe, guarantee that steel pipe all meets standard-required.

(3), production tube is carried out the water pressure test by propping up according to GB/T241-2007 " metal tube pressure testing test method ": 5MPa pressure, kept for 5 seconds, guarantee that steel pipe meets the density requirement of technical standard order.

4, sawing: fished pipe is carried out crop, back-end crop, the defective position of excision, make the fished pipe of warehouse-in all meet corresponding technical standard or technical protocol requirement.

5, the physicochemical property of steel pipe check

According to corresponding technical standard or technical protocol sampling production tube is carried out chemical composition, mechanical property, ballistic work and the examination of nonmetallic inclusion.Assay is as follows:

Steel pipe chemical composition (wt%)

S, P content and residual elements (Ni, Cu etc.) content are all well below national Specification in the chemical composition of the present invention that last table is put down in writing, and this is very favourable to the combination property that guarantees steel pipe.

The steel pipe mechanical property

The examination of nonmetallic inclusion

Claims (1)

1. the manufacturing process of a cold-drawing seamless steel tube for vehicular wrapped gas cylinder, it is characterized in that: adopt nominal dimension Φ 273 * 8.2 hot rolling mother tubes to expand through heat and expand mother tubes to Φ 415 * 7.5 heat and be cold drawing to Φ 406 * 5.9 trimmed size steel pipes again, concrete processing step is:

Heat expands technology: hot rolling mother tube Φ 273 * 8.2 heat expand to Φ 415 * 7.5:

(1) surfaces externally and internally quality, external diameter, the wall thickness of described specification Φ 273 * 8.2 hot rolling mother tubes of check select for use the same cross section hot-expanding pipe of wall thickness deviation below 1.0mm as mother tube;

(2) it is lubricated with graphitic lubricant heat to be expanded the mother tube inwall: graphite aqueous solution configuration requirement: 20 kilograms of graphite add 200 premium on currency;

(3) adjust the thermal expansion machine technological parameter: electric current 550～650A, voltage 450～500V, expansion speed 630mm/min;

(4) selected core print size: 400mm core print surface will be cleaned out, and evenly smears graphitic lubricant;

(5) the preceding high back of the preceding blanking rack of adjustment thermal expansion machine is hanged down and is carried out the heat expansion;

(6) after the heat expansion finishes, check hot-expanding pipe surface quality, wall thickness;

(7) hot-expanding pipe is carried out interior mill, grind off the remaining graphite of steel pipe;

Cold-drawing technology: hot-expanding pipe Φ 415 * 7.5 is cold drawing to Φ 406 * 5.9:

(1) pickling: chlorohydric acid pickling, concentration 30%, 40 ℃ ± 5 ℃ of temperature, soak time 6 hours;

(2) phosphatization: General Acidity in Phosphating Solution 20～25 points, free acid 2.0～2.5 points, 60～70 ℃ of temperature, soak time 30～35 minutes;

(3) saponification: saponification liquor aliphatic acid＞50 grams per liters, free acid＜5 grams per liters, 80～85 ℃ of temperature, soak time 5 minutes;

(4) steel pipe cold-drawn: pickling, lubricated qualified steel pipe carry out draw on 400 tons of hydraulic pressure cold drawing machines, by Φ 415 * 7.5 a time draws to Φ 406 * 5.9;

(5) production tube surface quality, physical dimension, out-of-roundness, flexibility control;

(6) fished pipe check.