CN105057389A - Method for directly extruding seamless tube by middle-chromium austenitic stainless steel continuous casting round billet - Google Patents

Abstract

The invention relates to the field of manufacturing of seamless steel tubes and particularly relates to a method for directly extruding a seamless tube by a middle-chromium austenitic stainless steel continuous casting round billet. The method for directly extruding the seamless tube by the middle-chromium austenitic stainless steel continuous casting round billet comprises the following steps: heating the continuous casting round billet to 1080-1160 DEG C and preserving the heat for 30-50 minutes; then removing phosphorus with high-pressure water and rolling and coating glass powder on the outer surface; under the protection of argon gas, heating the continuous casting round billet for the first time by using an induction furnace; heating the continuous casting round billet to 1160-1200 DEG C and preserving the heat for 5-10 minutes; machining a central through hole by using a deep hole drilling machine and chambering by using a perforating machine, wherein the chambering coefficient is 1.05-1.10; under the protection of the argon gas, heating the continuous casting round billet for the second time by using the induction furnace; heating the continuous casting round billet to 1200-1240 DEG C and preserving the heat for 2-4 minutes; and extruding the continuous casting round billet to a steel tube with a target size by using an extruder and controlling the extruding speed to be 0.3-1m/min.

Description

The method of the direct squeezing seamless pipe of a kind of middle chromium austenite stainless steel continuous casting circle base

Technical field

The present invention relates to seamless steel pipe and make field, specifically the method for the direct squeezing seamless pipe of a kind of middle chromium austenite stainless steel continuous casting circle base.

Background technology

Middle chromium austenite stainless steel is widely used in various corrosive environment due to the corrosion resistance of its excellence and formability, and product category various wherein steel pipe series products is a series products comparatively widely.The manufacturing process of usual seamless pipe has perforation and extruding, for the extrusion process of seamless pipe, in order to ensure extrusion process carry out smoothly and the performance of hollow forging qualified, its pipe needs to forge.This has strict dimensional requirement to ensure effective ratio of forging reduction to original steel ingot on the one hand; Adverse influence is had on the other hand to cost, production efficiency etc.

Summary of the invention

Technical problem to be solved by this invention is: how for the deficiency in background technology, provides a kind of needs to forge and the method for the middle chromium austenite stainless steel seamless pipe of straight forming.

The present invention says that the technical scheme of employing is: the method for the direct squeezing seamless pipe of a kind of middle chromium austenite stainless steel continuous casting circle base, carries out in accordance with the following steps:

Step one, continuous cast round billets is heated to 1080-1160 DEG C, insulation 30-50 minute, then dephosphorize by high pressure water, at outer surface roller coating glass dust;

Under step 2, argon shield, with induction furnace, first time heating is carried out to continuous cast round billets, be heated to 1160-1200 DEG C, insulation 5-10 minute, adopt deep hole rig machining center through hole, central through hole diameter is less than target tube internal diameter, and punch carries out reaming, expending die 1.05-1.10, namely completes 1.05-1.10 times that the through-hole diameter after reaming is target tube internal diameter;

Under step 3, argon shield, carry out second time heating, be heated to 1200-1240 DEG C with induction furnace to continuous cast round billets, insulation 2-4 minute, extruder is squeezed into the steel pipe of target size, and extruding rate controls at 0.3-1 m/min;

Step 4, cut into and need length, cold cut, remove glass dust, steel pipe is aligned, pickling.

The invention has the beneficial effects as follows: the present invention is the production that internal continuous cast round billets directly carries out squeezing seamless pipe, employing this method does not need the forging process in traditional handicraft process completely, operation expense and operation significant loss all can be saved on the one hand, greatly reducing production cost, is a kind of economical method for producing seamless steel tube; On the other hand owing to saving forging process, can greatly enhance productivity, the seamless pipe product simultaneously produced and the product surface quality that normal process is produced, mechanical property, grain size, enlarging and to flatten experimental result consistent even more excellent.

Detailed description of the invention

The principle of foundation of the present invention is the analysis by centering chromium austenite stainless steel as-cast structure, determines that optimum thermoplasticity is interval, considers that physical device and produced on-site situation are converted into actual field technique.Achieve first, by suitable heat treating regime, the as-cast structure in continuous casting billet is heated to optimum state, by suitable chambering process, mate finally by with extrusion speed, complete whole extrusion process, finally realize the direct extruding of continuous cast round billets.

Embodiment 1

Continuous cast round billets specification Φ 220mm, trimmed size Φ 89mm ╳ 10mm;

Step one, continuous cast round billets enter fire door furnace temperature 805 DEG C, annular furnace temperature: 1140 DEG C, temperature retention time: 30min, and continuous cast round billets is come out of the stove surface temperature 1140 DEG C, and then dephosphorize by high pressure water, at outer surface roller coating glass dust;

Under step 2, argon shield, with induction furnace, first time heating is carried out to continuous cast round billets, be heated to 1176 DEG C, be incubated 5 minutes, adopt deep hole rig machining center through hole, central through hole diameter is less than target tube internal diameter, and punch carries out reaming, expending die 1.06, namely completes 1.06 times that the through-hole diameter after reaming is target tube internal diameter;

Under step 3, argon shield, carry out second time heating with induction furnace to continuous cast round billets, be heated to 1208 DEG C, be incubated 3 minutes, extruder is squeezed into the steel pipe of target size, and extruding rate controls at 0.3 m/min;

Step 4, cut into and need length, cold cut, remove glass dust, steel pipe is aligned, pickling.

Surface quality is intact, without defects such as naked eyes visible cracks.

Embodiment 2

Continuous cast round billets specification Φ 480mm, trimmed size Φ 154mm ╳ 25mm;

Step one, continuous cast round billets enter fire door furnace temperature 803 DEG C, annular furnace temperature: 1150 DEG C, temperature retention time: 30min, and continuous cast round billets is come out of the stove surface temperature 1140 DEG C, and then dephosphorize by high pressure water, at outer surface roller coating glass dust;

Under step 2, argon shield, with induction furnace, first time heating is carried out to continuous cast round billets, be heated to 1186 DEG C, be incubated 8 minutes, adopt deep hole rig machining center through hole, central through hole diameter is less than target tube internal diameter, and punch carries out reaming, expending die 1.08, namely completes 1.08 times that the through-hole diameter after reaming is target tube internal diameter;

Under step 3, argon shield, carry out second time heating with induction furnace to continuous cast round billets, be heated to 1233 DEG C, be incubated 4 minutes, extruder is squeezed into the steel pipe of target size, and extruding rate controls at 0.9 m/min;

Step 4, cut into and need length, cold cut, remove glass dust, steel pipe is aligned, pickling.

Surface quality is intact, without defects such as naked eyes visible cracks.

Claims (1)

1. a method for the direct squeezing seamless pipe of chromium austenite stainless steel continuous casting circle base in, is characterized in that carrying out in accordance with the following steps:

Step one, continuous cast round billets is heated to 1080-1160 DEG C, insulation 30-50 minute, then dephosphorize by high pressure water, at outer surface roller coating glass dust;

Under step 2, argon shield, carry out first time heating, be heated to 1160-1200 DEG C with induction furnace to continuous cast round billets, insulation 5-10 minute, adopt deep hole rig machining center through hole, punch carries out reaming, expending die 1.05-1.10;

Under step 3, argon shield, carry out second time heating, be heated to 1200-1240 DEG C with induction furnace to continuous cast round billets, insulation 2-4 minute, extruder is squeezed into the steel pipe of target size, and extruding rate controls at 0.3-1 m/min;

Step 4, cut into and need length, cold cut, remove glass dust, steel pipe is aligned, pickling.