CN1411921A - Hot-rolling perforation-cold-rolling forming method for hollow rock-drill steel - Google Patents

Abstract

The present invention relates to a method for producing B and D type hollow rock-drill steel by using hot-rolling perforation-cold-rolling forming process. Said ivnention utilizes two-roll piercing mill to make the round solid billet whose diameter is 50-65 mm into hollow billet whose diameter is 50-65 mm and wall thickness is 6-17 mm, after the hollow billet is cooled, is can be cold-rolled and formed on the cold-rolling machine, so that said invented hollow rock-drill steel can be obtained.

Description

A kind of hot-puncturing process of hollow rock-drill steel-cold rolling forming method

Technical field

The invention belongs to the metal material processing technical field, a kind of hot-puncturing process-cold rolling forming method of hollow rock-drill steel particularly is provided.

Background technology

The hollow rock-drill steel is the main tool that is used for rock drilling such as mining, jewel hole.Regular size has hexagonal B19～B45 (the numeral opposite side distance is from mm) and circular D32～D51 (numeral diameter mm), its cross section as shown in Figure 1, the water injection hole at center is used for water flowing, dedusting and cooling.

The geometric properties of hollow rock-drill steel is: wall thickness (wall thickness is 1/3.2～1/3.5 with the ratio S/D of external diameter), endoporus little (minimum only is 5.5mm), length long (reaching 6mm most).In view of the geometric properties of above " like (steel) Guan Fei (steel) pipe ", this product can not adopt the production technology of seamless steel pipe fully, can not adopt the method for machining fully.Because the quality of endoporus has determined the counter-bending fatigue behaviour (main performance that is used to produce) of product to a large extent, so the mode of production of endoporus and quality thereof have become to distinguish the mode of production and have estimated the main foundation of its quality.

The existing mode of production of hollow rock-drill steel mainly contains following two kinds:

1, is published in " rock drilling machinery pneumatic tool " paper " the production wire of Sweden's hollow steel " in 1994 by Hu Ming, Qin Yan and proposes machine drilling-belt carcass hot rolling method.Its main technique flow process is seen Fig. 9.

The main feature of this technology is that the potassium steel plug that inserts is out of shape with blank, plug is extracted out after the cooling again.Because plug has played the effect of processing cored steel endoporus, therefore, defectives such as bore area flawless.The major defect of this technology is: operation is many, circle and the plug consumption big (plug can only roll a hollow rock-drill steel) of long flow path, endoporus.What foremost in the world Sweden Sandvik company adopted is this technology.

2, by leaf reach the clouds, Feng Zhi was published in " iron and steel " paper in brave 1996 " drill rod is worn-hot rolling working system production technology with cored steel heat " proposes roll piercing-oblique milling forming process.Its main technique flow process is seen Figure 10.

The main feature of this technology is to utilize roll piercing to obtain the heavy wall hollow billet, on the roller trio skew rolling elongator, and under the situation of cored bar not hollow billet is carried out big tube reducing distortion, has the advantage that flow process is short, equipment is few, production cost is low.The major defect of this technology is owing to there is not plug that acutely reversing of process pipe extended in the elaboration and the oblique milling of bore area, makes bore area defectives such as crackle, fold often occur, causes service life not high and unstable.Xianning mining machinery plant of China, new Fushun Steelworks adopt this production technology.

Summary of the invention

The quality of hollow rock-drill steel depends on following three links: the selection of steel grade and metallurgical quality, forming mode, heat treating regime.The present invention seeks to the high-quality B of production that proposes at forming mode, the molding mode of D type cored steel.

The present invention adopts hot-puncturing process-cold rolling method of forming to produce B, D type hollow rock-drill steel.Hot-puncturing process (Φ 50 Mannesmann piercing machines) is rolled into Φ 50～Φ 65mm with the circular solids pipe of Φ 50～Φ 65mm under hot state, the hollow hollow billet of wall thickness 6～17mm, cooling back roll forming on cold-rolling mill.

Two conventional rollers and three cold mills are to be used for the special equipment of production high accuracy thin-wall steel tube (S/D=1/60～1/250).The utility model utilizes the operating principle of cold-rolling mill, from the geometric properties (S/D=1/3.2～1/3.5) of cored steel,, realize specific deformation process by the instrument design, on three cold mills, produce B, D type product, on two-roll cold rolling mill, produce D type product.

Molding process:

When producing B, D type product on three cold mills, warp tool has three uiform sections (Type B is that triangle pass, D type such as are at radius arc shape pass) roll, three variable cross-section support plates and a cylindrical plug.The roll shaft of roll abuts against on the slideway of support plate, utilizes the variation of the special shape of slideway, realizes following deformation process: when roll moved to preceding extreme position (positive stroke), roll was drawn close, and the pass shape is consistent with shape of product; When roll moves to back extreme position (returning stroke), roll separately, and leave pipe and expect, turning round feed mechanism this moment will manage material and turn round certain angle (Type B is 60 °, the D type is 40 °～60 °) and send one section pipe material to, roll travels forward once more then, and this section pipe material of sending to is out of shape between roll and plug.Periodic motion so repeatedly is until hollow hollow billet is rolled into the hollow rock-drill steel.Deformed area and shaping principle are shown in figure two.

The deformed area L of above-mentioned deformation process increases wall section L by tube reducing ₁, wall-reducting section L ₂, pre-Strain During Finishing Stage L ₃, sizing section L ₄Form the acting as of each section:

L ₁: finish the distortion of most of tube reducing, in tube reducing, wall thickness has more significantly to increase and (is about 1～1.2mm); The bight begins to form.

L ₂: finish and subtract wall distortion, wall thickness reducing amount equals or is slightly larger than the wall thickness that increases in the L1 section; The bight is full of.

L ₃: shape and size reach product requirement.

L ₄: geomery is accurate, and surfaces externally and internally is bright and clean.

When producing D type product on two-roll cold rolling mill, warp tool has roll and conic mandrel bar of two variable cross-sections, and deformation process and deformed area composition and three cold mills are basic identical.

Technological parameter:

Relative reducing rate: $\frac{D_0-d}{D_0}\×100\%=15~30\%$

Relative wall cut rate: $\frac{S_0-s}{S_0}\×100\%=0~10\%$

Lengthening coefficient: μ=1.5～2.5

The hollow pipe material: $\frac{S_0}{D_0}=\frac{1}{4.0}~\frac{1}{4.5}$

Finished product: $\frac{s}{d}=\frac{1}{3.2}~\frac{1}{3.5}$

In the formula:

D ₀, d-hollow pipe material, finished product external diameter, mmS ₀, S-hollow pipe material, finished product wall thickness, mm deformed area parameter:

L ₁＝(0.3～0.5)L

L ₂＝(0.4～0.3)L

L ₃＝(0.2～0.1)L

L ₄=0.1L the invention has the advantages that:

1, operation is few, and flow process is short.

Master operation is: with circular pipe blank heating back hot-puncturing process, cold rolling then moulding (once moulding on cold-rolling mill).See Figure 11

2, good product quality.

Because plug is participated in distortion, guaranteed the inner surface quality in water hole; Plug can use repeatedly; Inside and outside

Any surface finish, shape and size are accurate, can realize rolling with negative tolerance.

3, have a extensive future.

There is many steel pipe's production producer in China, and for example existing Φ 50mm punch of Ningbo Tianzhu Steel Tube Special Co., Ltd and cold pilger mill make improvements slightly to existing production line, can production hollow rock-drill steel.

Description of drawings

The present invention is further described below in conjunction with accompanying drawing:

Fig. 1 is a three roll pipe category-B product roll shape schematic diagram.D _mBe roll maximum gauge, D _pBe diameter at the bottom of the roller, D _gBe the roll neck diameter; B is a category-B product roll pass width, and b is a category-B product roll collars width.

Fig. 2 is three roll pipe D series products roll shape figure.D _m, D _p, D _gBe respectively diameter at the bottom of roll maximum gauge, the roller, roll neck diameter; R, B, b: be respectively roll pass radius, hole slot width, collars width.

Fig. 3 is a three roll pipe gripper shoe schematic diagram.Wherein: β ₁, β ₂, β ₃, β ₄: be respectively each section of gripper shoe cone angle; H ₁, H ₂, H ₃: be respectively gripper shoe total height, anti-awl section height and idle running section height; S ₁S ₂: be respectively the idle end thickness of slab, the anti-end plate of boring is thick; L, B, b, h: be respectively gripper shoe length, width, sidewall thickness, anti-awl section falling head.

Fig. 4 is a three roll pipe plug schematic diagram.Wherein φ is the three roll pipe diameter of mandrel; L is a three roll pipe plug length.

Fig. 5 is two a rolling tube cores rod schematic diagram.Wherein: D ₁D ₂D ₃Be respectively each section of two rolling tube cores rod diameter; l ₁l ₂l ₃Be respectively each segment length of two rolling tube cores rod; β is two a rolling tube cores rod cone angle.

Fig. 6 is category-B, D class drill steel schematic cross-section.The limbers is with thousand dedustings and cooling.

Fig. 7 forming technology schematic diagram.Wherein scheme A and be the back extreme position, figure B is preceding extreme position, and figure C is the gripper shoe right view.Roll 1, pipe material 2, plug 3, gripper shoe 4, finished product 5.

Fig. 8 is rolling B22 type hollow rock-drill steel schematic diagram.

Fig. 9 is machine drilling-belt carcass hot rolling method process chart.

Figure 10 is roll piercing-oblique milling forming process process chart.

Figure 11 is the short flow process process chart of the present invention.

The specific embodiment

Example 1: adopt heating of pipe blank stove, Φ 50 two-roll piercers, the rolling B28 of LD-30 three cold mills, B32 pipe.

Example 2: adopt heating of pipe blank stove, Φ 50 two-roll piercers, the rolling D38 of LD-30 three cold mills, B32 pipe.

Claims (3)

1, a kind of hot-puncturing process of hollow rock-drill steel-cold rolling forming method, it is characterized in that: adopt hot-puncturing process-cold rolling method of forming to produce B, D type hollow rock-drill steel, hot-puncturing process Φ 50 Mannesmann piercing machines are rolled into Φ 50～Φ 65mm with the circular solids pipe of Φ 50～Φ 65mm under hot state, the hollow hollow billet of wall thickness 6～17mm, cooling back roll forming on cold-rolling mill.

2, forming method according to claim 1, it is characterized in that: when on three cold mills, producing B, D type product, warp tool has three uiform sections: Type B is that triangle pass, D type such as are at radius arc shape concave roll, three variable cross-section support plates and a cylindrical plug; The roll shaft of roll abuts against on the slideway of support plate, utilizes the variation of the special shape of slideway, realizes following deformation process: during extreme position, roll is drawn close before roll moves to, and the pass shape is consistent with shape of product; When roll moves to the back extreme position, roll separately, and leave the pipe material, and turn round feed mechanism this moment and will manage material revolution certain angle, wherein Type B is 60 °, the D type is 40 °～60 °, and send one section pipe material to, roll travels forward once more then, and this section pipe material of sending to is out of shape between roll and plug, periodic motion so repeatedly is until hollow hollow billet is rolled into the hollow rock-drill steel; The deformed area L of deformation process increases wall section L by tube reducing ₁, wall-reducting section L ₂, pre-Strain During Finishing Stage L ₃, sizing section L ₄Form, wherein L ₁Finish most of tube reducing distortion, in tube reducing, wall thickness has more significantly to be increased, and is 1～2mm; The bight begins to form; L ₂Finish and subtract wall distortion, wall thickness reducing amount equals or is slightly larger than at L ₁The wall thickness of Duan Zengjia; The bight is full of; L ₃Shape and size reach product requirement; L ₄Geomery is accurate, and surfaces externally and internally is bright and clean.

3, according to claim 1 or described forming method, it is characterized in that: when on two-roll cold rolling mill, producing D type product, warp tool has roll and conic mandrel bar of two variable cross-sections, and deformation process and deformed area composition and three cold mills are basic identical, technological parameter:

Relative reducing rate: $\frac{D_0-d}{D_0}\×100\%=15~30\%$

Relative wall cut rate: $\frac{S_0-s}{S_0}\×100\%=0~10\%$

Lengthening coefficient: μ=1.5～2.5

The hollow pipe material: $\frac{S_0}{D_0}=\frac{1}{4.0}~\frac{1}{4.5}$

Finished product: $\frac{s}{d}=\frac{1}{3.2}~\frac{1}{3.5}$

In the formula: D ₀, d is hollow pipe material, finished product external diameter, S ₀, s is the wall thickness of hollow pipe material, finished product;

Deformed area parameter: L ₁=(0.3～0.5) L, L ₂=(0.4～0.3) L, L ₃=(0.2～0.1) L, L ₄=0.1L.

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