CN104325259A - Manufacturing method of seamless steel pipe piercing plug - Google Patents

Abstract

The invention relates to a manufacturing method of a piercing plug, in particular to a manufacturing method of a seamless steel pipe piercing plug. The method comprises the following steps: (1) casting a steel ingot; (2) forging round steel, namely heating the steel ingot to 980-1,000 DEG C and forging by using a vacuum hammer; (3) performing die forging, namely preserving the heat of the round steel obtained by the step (2) at 980-1,000 DEG C and making the round steel into a blank through die forging; (4) performing heat treatment, namely keeping the blank at the temperature of 680 DEG C for 8 hours, cooling in a furnace to 300 DEG C and then performing air cooling; (5) performing metalworking, namely machining the blank after heat treatment of the step (4) into a required product by using a numerical control lathe; (6) performing heat treatment again, namely nitriding the product obtained in the step (5) at 800-900 DEG C and oxidizing at 900-1,050 DEG C. The piercing plug prepared by using the method has high density, high strength and high wear resistance, the quality is quite stable during piercing, the service life is also doubled, the method is suitable for rolling alloy pipes, the cost performance is higher than H13 or a full-molybdenum piercing plug, and the cost is 1/3 of the H13 product and is 1/10 of the full-molybdenum product.

Description

A kind of manufacture method of piercing plug for seamless steel tubes

Technical field

The present invention relates to the manufacture method of perforating head, especially a kind of manufacture method of piercing plug for seamless steel tubes.

Background technology

The diversification of China's Metallurgy Industry current seamless steel pipe material, also increase using the requirement of top during perforation thereupon, top is the quality of the key tool quality in seamless steel tube production, piercing in seamless steel pipe process, solid pipe billet is made hollow hollow billet, the distortion of metal is mainly carried out on top, so the working condition of top is quite severe, not only to bear powerful axial compressive force, and the powerful distortion friction produced between inwall will be overcome, so require that top has higher intensity, wearability, and have higher requirement to the service life of top.

High alloy material steel pipe generally all selects H13 mould steel or full molybdenum plug, and H13 belongs to hot die steel, is the steel grade adding alloying element and formed on the basis of carbon steel, for the manufacture of the forging die that shock loading is large, and hot extruding die, precision forging die; Aluminium, copper and alloy die-casting thereof, hot-extrusion mold, high speed finish forge mould and forging press mould etc., but cost intensive, manufacturing cost is high; Full molybdenum plug cost is more expensive, and the production cost of manufacturer is significantly increased.

Summary of the invention

For deficiency of the prior art, the invention provides a kind of manufacture method of lower-cost piercing plug for seamless steel tubes.

In order to solve the problems of the technologies described above, the present invention is solved by following technical proposals, and a kind of manufacture method of piercing plug for seamless steel tubes, comprises the steps:

1) steel ingot is cast: 20CrNi4 cast is become steel ingot, and the concrete composition weight percentage of 20CrNi4 calculates following C:0.15-0.30%, Cr:1.0-1.9%, Ni:3.0-4.5%, Mn:0.3-0.7%, W:0.4-0.5%, Mo:0.2-0.4%, all the other are Fe;

2) round steel is forged: by Heating Steel Ingots to 980-1000 DEG C, make with vacuum hammering;

3) die forging: by step 2) obtain round steel insulation at 980-1000 DEG C, make blank by die forging;

4) heat treatment: air cooling after 300 DEG C were cooled to the furnace in 8 hours to blank 680 DEG C insulation;

5) metalworking: by step 4) blank lathe in machining after heat treatment becomes required product;

6) heat treatment again: to step 5) product that obtains carries out nitrogen treatment at 800-900 DEG C, and 900-1050 DEG C is carried out oxidation processes.

Compared with prior art, original casting technique is changed into Forging Technology by the present invention, distance between the molecule of composition product diminishes due to 2 forging processing, the molecule that can hold in same distance is more, thus the density of product also just improves, the intensity that density improves top have also been obtained raising, also more wear-resisting, quality also quite stable during perforation, service life is significantly improved, piercing of compo pipe can be applicable to, than using, the cost performance of H13 mould steel or full molybdenum plug is high, cost is 1/3 of H13 mould steel top, 1/10 of full molybdenum plug.

Accompanying drawing explanation

Fig. 1 is process chart of the present invention.

Detailed description of the invention

Below in conjunction with accompanying drawing 1 and specific embodiment, the present invention is further explained.

Embodiment 1:

Step 101: casting steel ingot: 20CrNi4 cast is become steel ingot, and the concrete composition weight percentage of 20CrNi4 calculates following C:0.15%, Cr:1.0%, Ni:3%, Mn:0.3%, W:0.4%, Mo:0.2%, and all the other are Fe;

Step 102: forging round steel: by Heating Steel Ingots to 980 DEG C, make with vacuum hammering, improves materials microstructure density;

Step 103: die forging: first steel insulation step 102 obtained is at 980-1000 DEG C, make blank by die forging, make blank by die forging, because green density is high, intensity is good, product wall thickness can subtract book, cooling performance is largely increased, and can improve 5-6 service life doubly;

Step 104: heat treatment: air cooling after 300 DEG C were cooled to the furnace in 8 hours to blank 680 DEG C insulation, heat-treat herein and mainly eliminate product stress, because top service condition is severe, rapid heat cycle, product easily forms stress and ftractures, if eliminate product stress to the greatest extent, the service life of product can be increased substantially;

Step 105: metalworking: the blank lathe in machining after step 104 heat treatment is become required product;

Step 106: heat treatment again: at 800 DEG C, nitrogen treatment is carried out to the product that step 105 obtains, 900 DEG C are carried out oxidation processes, to increase surface smoothness and corrosion resistance formation carburization zone, the metallographic structure of product is after treatment ferrite+granular bainite.

Embodiment 2:

Substantially the same manner as Example 1, difference is:

In step 101, the concrete composition weight percentage of 20CrNi4 calculates following C:0.3%, Cr:1.9%, Ni:4.5%, Mn:0.7%, W:0.5%, Mo:0.4%, and all the other are Fe;

By Heating Steel Ingots to 1000 DEG C in step 102;

Round steel insulation step 102 obtained in step 103 is at 1000 DEG C;

Carry out nitrogen treatment to the product that step 105 obtains at 900 DEG C in step 106,1050 DEG C are carried out oxidation processes.

The present invention compares with original cast article, improves 5-6 service life doubly, certain factory 273 unit uses result, and wear 200-250 arm from original every only top and bring up to a top and wear 600-800 arm, effect is quite obvious.When piercing alloy pipe, 150-180 can be reached prop up/only, there is good elevated temperature strength.Wearability, anti-chilling, anxious heat, fatigue resistance are all better than like product.In use procedure lubrication and effect of heat insulation outstanding, not easily steel bonding.

Only as described above, be only preferred embodiment of the present invention, such as professional who are familiar with this art.After understanding technological means of the present invention, natural energy, according to actual needs, is changed under the teachings of the present invention.Therefore all equal changes of doing according to the present patent application the scope of the claims and modification, all should still remain within the scope of the patent.

Claims (1)

1. a manufacture method for piercing plug for seamless steel tubes, is characterized in that, comprises the steps:

1) steel ingot is cast: 20CrNi4 is cast as steel ingot, and the concrete composition weight percentage of 20CrNi4 calculates following C:0.15-0.30%, Cr:1.0-1.9%, Ni:3.0-4.5%, Mn:0.3-0.7%, W:0.4-0.5%, Mo:0.2-0.4%, all the other are Fe;

2) round steel is forged: by Heating Steel Ingots to 980-1000 DEG C, make with vacuum hammering;

3) die forging: by step 2) obtain round steel insulation at 980-1000 DEG C, make blank by die forging;

4) heat treatment: air cooling after 300 DEG C were cooled to the furnace in 8 hours to blank 680 DEG C insulation;

5) metalworking: by step 4) blank lathe in machining after heat treatment becomes required product;

6) heat treatment again: to step 5) product that obtains carries out nitrogen treatment at 800-900 DEG C, and 900-1050 DEG C is carried out oxidation processes.