CN102407425A

CN102407425A - Method for manufacturing ventilated steel tube made of hull steel

Info

Publication number: CN102407425A
Application number: CN2010102918522A
Authority: CN
Inventors: 李友胜
Original assignee: SHANGHAI YUEYUECHAO STEEL TUBE CO Ltd
Current assignee: SHANGHAI YUEYUECHAO STEEL TUBE CO Ltd
Priority date: 2010-09-26
Filing date: 2010-09-26
Publication date: 2012-04-11

Abstract

The invention discloses a method for manufacturing a ventilated steel tube made of hull steel, which comprises the following steps: cutting into strips, i.e. vertically cutting a steel plate; milling edges, i.e. milling the two side edges of the steel plate at a time; prebending, i.e. removing straight flanges of the end of the plate; bending, i.e. primarily bending the steel plate into a cylinder shape; molding, i.e. molding the cylinder-shaped steel plate into the steel tube; closing a joint and prewelding, i.e. carrying out joint close on the connecting end of the steel tube; internal welding, i.e. welding the inner part of the connecting end of the steel tube; external welding, i.e. welding the external part of the connecting end of the steel tube; machining a tube end, i.e. machining a flat end of the tube end of the steel tube; straightening, wherein straightness accuracy being up to standard can be reached only through straightening; finishing, i.e. forcibly finishing through an O-shaped mould; trimming an end, i.e. enabling the end of the steel tube to be smooth; final detecting, i.e. detecting the steel tube; and warehousing, i.e. warehousing after the steel tube is detected to be qualified. A measure for preventing the occurrence of longitudinal cracks of a welding seam is controlling circular degree of prebending and prefinishing before internal welding.

Description

The manufacturing approach of hull steel ventilation steel pipe

Technical field

The present invention relates to a kind of manufacturing approach of steel, particularly relate to a kind of manufacturing approach of hull steel ventilation steel pipe.

Background technology

Development along with shipbuilding industry; Use on a large scale in hull steel (the especially KSTPG42 type hull steel) shipbuilding; KSTPG42 type hull steel is Nippon kaiji kyokai's standard; Present Japanese KSTPG42 hull steel ventilation steel pipe is mainly used the seamless steel pipe manufacturing, but seamless steel pipe manufacturing cost height and specification be restricted, and the KSTPG42 hull steel ventilation steel pipe of my company's exploitation is with alternative part seamless steel pipe; Yield strength >=the 215Mpa of KSTPG42 type hull steel (its chemical composition is as shown in table 1), tensile strength is greater than 370Mpa.Intensity and hardness are higher, very likely crack after difficult forming and the welding, and the moulding difficulty increases along with plate thickness and strengthens, and mainly is the difficulty of pre-bending bending joint close and integer; Thereby welding causes carbon equivalent higher because of alloying component is higher, and solderability is reduced, and the steel heat affecting is easy to generate the inductile hardened structure, and hardenability also is easy to generate crackle along with the thickness increase.

The chemical composition of table 1 KSTPG42 type hull steel

Model

C

Si

Mn

P

S

Cu

KSTPG42

≤0,30

≤0,35

0.3-1.0

≤0,040

Summary of the invention

In order to solve the technical problem of steel pipe toughness after problem, difficult forming and the welding that seamless steel pipe cost height that hull steel ventilation steel pipe in the prior art uses and specification be restricted, the invention provides a kind of manufacturing approach of hull steel ventilation steel pipe.

The present invention realizes through following steps:

Step 1: open bar, a block plate is carried out perpendicular cuts;

Step 2: mill the limit, to the dual-side of steel plate through a Milling Process;

Step 3: pre-bending, pre-bending are to eliminate plate end straight flange, bend circular arc to the side of steel plate earlier, repeatedly are bent to the circular arc requirement with the standard patrix again;

Step 4: bending tentatively is converted into tubular with steel plate;

Step 5: moulding, the steel plate formation steel pipe with tubular compresses the steel pipe whole circumference during moulding, makes even along the residual stress on thickness of steel pipe and the circumferencial direction;

Step 6: the joint close prewelding, carry out joint close with the link of steel pipe;

Step 7: interior weldering, interior weldering is welded the link inside of steel pipe;

Step 8: outside weld, outside weld is welded the link outside of steel pipe;

Step 9: pipe end processing, carry out the pipe end tack processing of steel pipe;

Step 10: aligning needs through just reaching the linearity that standard allows behind the aligning;

Step 11: finishing, force accurate shaping with O shape mould;

Step 12: repair end, make the termination of steel pipe level and smooth;

Step 13: the final detection, steel pipe is detected;

Step 14: warehouse-in, steel pipe detects warehousing after passing and deposits.

Preferably, mariages automatic submerged arc welding is adopted in said interior weldering.

Preferably, the automatic submerged arc welding of mariages multilayer multiple tracks is adopted in said outside weld.

Preferably, said final detection comprises that ultrasound examination, X ray detect, magnetic detects, Non-Destructive Testing.

Positive progressive effect of the present invention is: the present invention prevents that the main technique measure of quenching of heat affected area from being control weld heat input and welding parameter, reduces high-temperature residence time, improves the toughness of steel pipe seam greatly; The measure that the present invention prevents to produce the weld seam longitudinal crack is to carry out preparatory finishing before control pre-bending bending circularity and the interior weldering prerequisite.

Description of drawings

Fig. 1 is the flow chart of one embodiment of the invention.

The specific embodiment

Provide preferred embodiment of the present invention below in conjunction with accompanying drawing, to specify technical scheme of the present invention.

The manufacturing approach of hull steel ventilation steel pipe of the present invention is used to make KSTPG4 type hull steel ventilation steel pipe.As shown in Figure 1, the manufacturing approach of hull steel ventilation steel pipe of the present invention may further comprise the steps:

Step 1: open bar, a hull steel steel plate is carried out perpendicular cuts;

Step 3: pre-bending, pre-bending mainly are to eliminate plate end straight flange, bend circular arc to the side of steel plate earlier, repeatedly are bent to the circular arc requirement with the standard patrix again, have so not only satisfied the pre-bending requirement but also have practiced thrift steel plate materials; The high pre-bending of invar intensity does not reach eliminates the straight flange requirement, changes original pre-bending, a pre-bending several times.

Step 4: bending tentatively is converted into tubular with steel plate; Emphasis control bending circularity, circularity generally is controlled in 20 millimeters, avoids shaping to cross ambassador's weld seam because of roundness deviation and longitudinal crack occurs.

Step 5: moulding; The steel plate of tubular is formed steel pipe, during moulding the steel pipe whole circumference is compressed, make even along the residual stress on thickness of steel pipe and the circumferencial direction; Can be reduced to the stress of shape steel tube on the one hand, provide convenience for postorder joint close prewelding on the other hand;

Step 7: interior weldering, interior weldering is welded the link inside of steel pipe, and monofilament automatic submerged arc welding is adopted in interior weldering, shaping and the weld seam longitudinal crack occurs again after avoiding all having welded; Weld preheating welded seam area, preheating width are in 100 millimeters on the weld seam both sides, and preheat temperature 150 is spent to 200 degree.

Step 8: outside weld, outside weld is welded the link outside of steel pipe, and the automatic submerged arc welding of monofilament multilayer multiple tracks is adopted in outside weld; Weld preheating welded seam area, preheating width are in 100 millimeters on the weld seam both sides, and preheat temperature 150 is spent to 200 degree.

Step 11: finishing, force accurate shaping with O shape mould, to reach higher circularity and straight degree;

Step 12: repair end, make the termination of steel pipe bright and clean level and smooth;

Step 13: the final detection, steel pipe to be detected, the final detection comprises ultrasound examination, X ray detection, magnetic detection, Non-Destructive Testing, hydraulic pressure detection and takes advantage of magnetic to detect;

The present invention prevents that the main technique measure of quenching of heat affected area from being control weld heat input and welding parameter, reduces high-temperature residence time, improves the toughness of steel pipe seam greatly; The measure that the present invention prevents to produce the weld seam longitudinal crack is to carry out preparatory finishing before control pre-bending bending circularity and the interior weldering prerequisite.

Though more than described the specific embodiment of the present invention, it will be understood by those of skill in the art that these only illustrate, under the prerequisite that does not deviate from principle of the present invention and essence, can make numerous variations or modification to these embodiments.Therefore, protection scope of the present invention is limited appended claims.

Claims

1. the manufacturing approach of a hull steel ventilation steel pipe, realize through following steps:

Step 1: open bar, a block plate is carried out perpendicular cuts;

Step 4: bending tentatively is converted into tubular with steel plate;

Step 8: outside weld, outside weld is welded the link outside of steel pipe;

Step 11: finishing, force accurate shaping with O shape mould;

Step 12: repair end, make the termination of steel pipe level and smooth;

Step 13: the final detection, steel pipe is detected;

2. the manufacturing approach of hull steel ventilation steel pipe as claimed in claim 1 is characterized in that, monofilament automatic submerged arc welding is adopted in said interior weldering.

3. the manufacturing approach of hull steel ventilation steel pipe as claimed in claim 1 is characterized in that, the automatic submerged arc welding of monofilament multilayer multiple tracks is adopted in said outside weld.

4. the manufacturing approach of hull steel ventilation steel pipe as claimed in claim 1 is characterized in that, said final detection comprises that ultrasound examination, X ray detection, magnetic detection, Non-Destructive Testing, hydraulic pressure detect and take advantage of the magnetic detection.