JPS599154A - Material for tool for manufacturing seamless steel pipe - Google Patents

Abstract

PURPOSE:To obtain a material for a tool for manufacturing a seamless steel pipe with improved wear resistance at high temp., by forming a cast steel contg. specified amounts of C, Si, Mn, Cr, Ni, Mo and Nb and by heat-treating it in an oxidizing atmosphere. CONSTITUTION:An alloy steel consisting of, by weight, 0.20-0.60% C, 0.10-2.0% Si, 0.30-2.0% Mn, 1.0-6.0% Cr, 1.0-6.0% Ni, 0.50-5.0% Mo, 0.20-1.5% Nb and the balance Fe with inevitable impurities or further contg. one or more among 0.05-2.0% Al, 0.05-2.0% Zr, 0.10-0.80% V, 0.50-5.0% Co and 0.50- 5.0% W is manufactured. The cast alloy is formed and heat-treated at 900- 1,250 deg.C in an oxidizing atmosphere to produce scale having a thickness enough to provide a sufficient heat insulating effect. The resulting material for a tool for manufacturing a seamless steel pipe has superior wear resistance at high temp., so it is applicable to a plug for forming, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tool material for manufacturing seamless steel pipes, and more particularly to a tool material with excellent wear resistance at high temperatures and a long life.

The general method for manufacturing seamless steel pipes is to create a hollow material by perforating a round steel piece or square steel piece using the Mannesmann method or press method, and then stretching this hollow material using a rolling machine such as an elongator, plug mill, or mandrel. It is true.

In each step of manufacturing this seamless steel pipe, the forming plug and guide shoe are exposed to severe abrasion conditions at high temperatures. Therefore, manufacturing tools with high wear resistance at high temperatures and extending tool life is one of the important issues in the production of seamless steel pipes using the above method. Demand for increased production and higher alloys
Its importance is becoming even greater when it comes to power.

The purpose of the present invention is to meet the demand for improvements in the prior art, and to provide a T for the production of seamless steel pipes with excellent wear resistance at high temperatures.
We provide filling materials.

The inventors of the present invention have conducted repeated experiments with a focus on the lifespan of plugs for use with elongators that straddle the hole. One way to improve the wear resistance of wood materials at high temperatures is to increase the high temperature strength of general wood materials, and for this purpose, alloying elements such as C, Cr, Mo, W, etc. However, when these alloying elements are increased, the general (C thermal conductivity t': l:, -i f'?:, F
4IJi points decrease. Seamless steel pipe - 1il! ! If the thermal conductivity of the plug is poor when it is constantly in contact with a high-temperature material to be deformed, such as a plug during manufacturing, the heat input from the material to be deformed will be concentrated on the surface, and the temperature of the surface will be It's nice.

Moreover, if the melting point is low, the surface tends to become molten, resulting in significant wear and tear on the plug surface.

Therefore, the addition of alloying elements is limited to 311, and the high temperature strength is -
There are limits to L elevation.

In a drilling or elongator, the deformation temperature of the plug mill blank tube is high, and the ratio of the thickness of the material to be deformed in the portion that contacts the plug during drilling or elongation to the diameter of the plug is large, so the amount of heat input to the plug is large. Therefore, the plug material for the elongator in the current drilling industry is focused not on high-temperature strength but on not reducing good thermal conductivity, and has a low alloy composition. However, current materials have the disadvantage of low high 6q strength, and are no longer able to cope with the recent improvements in production efficiency and high alloying of seamless copper pipes for oil wells.

The inventor of the present invention took all of the above points into account and conducted an experiment.

1. A component system that can effectively increase the high temperature strength by adding stitches in a range that completely degrades the thermal conductivity of the material.

It has been found that the surface of a molded product made from a cast alloy of this composition has good adhesion to the base alloy, and that an oxide scale of f' can be easily formed on the surface of the molded product. The present invention 1/i was made based on this knowledge).

The gist of the first invention is as follows. That is, at 1 weight ratio <=: 020 to 060%, St
: 0.10~2.0%, Mn: 0.30~2.0
%, Cr=1.0~6.0%, Ni:1.0~6.0
%, Mo: (1,50-5.0%, Nb
: After being molded from a cast alloy containing +1.20 to 1.5% and the remainder consisting of Fe and unavoidable impurities, it was heat-treated at a temperature range of 900 to 1250°C in an oxidizing atmosphere. This is a tool material for manufacturing seamless steel pipes.

The gist of the second invention is that in addition to the same basic composition as the first invention, A7: 0.05 to 20%.

Zr: 0.05-2.0%, V: 0.10
~0.80%, co:o, 50~5.0%, W'0.4
A cast alloy of two or more types selected from Ml ~ 5.0%, the entire residual part of which is composed of Fe and unavoidable impurities, is heat-treated in the same manner as in the first invention. It is.

Next, the reasons for limiting the alloy components in the present invention will be explained.

C: Chemical C1-j: Added as an element that improves high-temperature wear resistance by forming large carbon particles such as (Cr, Mo, Nl), but if it is less than 1020%, the effect is small, and if it exceeds 060%, the melting point will be lowered. Since a decrease in the amount of carbon dioxide actually worsens the abrasion properties, it is limited to a range of 0.20 to 0.60%.

Si: Is Si a scale that has good adhesion to the base metal alloy? Generation-g
Although it is added to oxidize, if it is less than 10% gold, the effect will be small, and if it exceeds 2.0% gold, the high temperature strength will decrease, so 0.1% gold is added.
It was limited to a range of 0 to 20%.

hen: Mn is added to increase high temperature strength 75;, 03
If it is less than 0%, the effect will be small, and if it exceeds 2.0%, the thermal conductivity will deteriorate and the high temperature wear resistance will deteriorate, so the lower limit was set to 0.30% and the upper limit was set to 20%.

Cr: Cr produces a scale on the surface that has good adhesion to the base metal alloy and has good insulation properties, and increases high-temperature strength by forming a sweet Cr proboscis.

If it is less than 10%, the effect will be small, and if it exceeds 6.0%, the amount of scale produced will be reduced, the thermal conductivity will be impaired, and the high temperature wear resistance will be completely deteriorated, so the content was limited to a range of 10 to 60%.

NI: Ni is added to form a school with good adhesion to the base metal alloy, but if it is less than 10%, it is insufficient.
If it exceeds 0%, the production capacity of scale/l decreases, the thermal conductivity deteriorates, and the high temperature wear resistance deteriorates, so 1.
It was limited to a range of 0 to 60%.

Mo/MO increases the width strength by solid solution hardening and carbide formation 1 (/C is effective, but Q, r is not effective below 050% 117), so the lower limit k is set to 0.50%, and 50 %
If it exceeds 50%, scale formation will be significantly reduced and high-temperature wear resistance will be deteriorated, so the limit was limited to 50%.

Nb; significantly increases high-temperature strength due to the formation of bI-i carbides; h+
However, if it is less than 0.2 (1%), the effect is small. Therefore, the upper limit was set at 15%.

The above C, Si, Mn, (?r, Ni, Mo
, Nb are the basic components of the rolling tool monthly charge of the present invention, and in addition, At, Zr, V, Co, and Wf are contained in the limited circles below. The purpose of the present invention can also be more effectively achieved with the use of a base material for use as a rolling stock containing the same. The reasons for these limitations are as follows.

A/=, Zr: Al-, 7, and r are both necessary to produce a school with good adhesion to the base steel and good heat insulation (they are added as needed, but if it is less than 0.05%, the effect is small, If it exceeds 2.0%, the number of scales generated will be significantly reduced.

Since they deteriorate high-temperature wear resistance, both Al, Zr and Zr were limited to a range of 0.05 to 2.0%.

V: (1) has the effect of increasing high-temperature strength by forming carbides, but if it is less than 0.10%, it has no effect.

If it exceeds 0.80%, the effect is saturated and it is also expensive, so it is limited to a range of 0.10 to 0.80%.

Co: has the effect of increasing high-temperature strength through CO solid solution hardening, but if it is less than 0.50%, the effect is small, and if it exceeds 5.0%, it reduces scale formation and actually deteriorates the high-temperature wear resistance completely. 0.
! It was limited to a range of Ml to 50%.

W: W has the effect of increasing high-temperature strength through solid solution hardening and carbide formation, but if it is less than 0.50%, the effect is small, and if it exceeds 5.0%, it forms coarse carbides and deteriorates toughness. It was limited to a range of 0.50 to 50%.

Next, a description will be given of heat treatment of a material molded from a cast alloy having the above-mentioned limited components. Naturally, if the post-molding heat treatment is performed in an atmosphere other than an oxidizing atmosphere, the necessary oxide scale cannot be obtained.

Next, basic experiments on heat treatment will be explained.

That is, after forming perforated plugs from the present invention materials jK1 and 2, whose chemical compositions are shown in Table 1, they were heated in the atmosphere for 8 hours.
Heat treatment for 4 hours in the temperature range of 00 to 1300°C, C: 022%, Si: 0.25%, Mn: 1.
30%, Ti: 0.020%, l'3: 0.0
020%, a billet with a diameter of 207fl was continuously perforated and its lifespan was investigated.

Table 1 At the same time, conventional materials with the chemical compositions shown in Table 1 were exposed to 950℃ in the atmosphere.
The plugs that had been heat treated for 4 hours at ℃ were also drilled in the same manner as above, and the relationship between the lifespan and heating temperature of the Al material containing the ingredients of the present invention, Ya 2, with the lifespan of this conventional material as 1. Shown in the drawing.

However, in the attached drawings, ○ indicates Jf61 material, and 1d indicates O2 material.

In the accompanying drawing, it is seen that the lifespan is significantly reduced when the heating temperature is outside the range of 900 to 1250°C.
3 Table 022%, Si: 0.25%, Mn: I,
, 30%, l'i:(')02(1%, R:0.002
0%, diameter 207cm.As is clear from the plug life ratios in Table 3, all five inventive materials have a similar lifespan.

As is clear from the above examples, the present invention limits the components of the tool material for seamless steel pipe production, and in an oxidizing atmosphere,
By applying heat treatment in the temperature range of 00 to 125°C, it was possible to produce a tool material with excellent wear resistance and long life.

Although the present invention has been mainly explained as a plug VM for a perforation spanning elongator in the seamless pipe manufacturing process, the material of the present invention can also be applied to a mandrel perfor seamless steel pipe manufacturing. can.

[Brief explanation of drawings]

The attached drawing is a correlation diagram showing the relationship between the surface oxide scale deposition IJn thermal temperature of a perforated plug for creating seamless steel pipes and the life of the plug. Agent Nakaji 'Li (male)

Claims (1)

[Claims] (1) C: o, zo ~ 0.60% by weight,
Si: 0.10 to 2.0%, Mn!
0.30 to 2.0%, Cr:1
, O~6.0%, Ni: 1. o~6.0%, Mo
: 0.50 to 5.0%, Nb: 0.20 to 1.5% (-1 After molding from a cast alloy with the balance consisting of Fe and unavoidable impurities, 90 () to I2 in an oxidizing atmosphere)
It has been subjected to heat treatment in the temperature range of 50°C! ! ij
A tool material for manufacturing seamless steel pipes. Q) C: 0.20-0.60%, Si: 0 in weight ratio
．． 10-2.0%, Mn: 0.30-2.0%,
Cr: 1.0-60%, Ni: 1.0-60%, M
o: 0.50 to 5.0%, Nb: 0.20 to 15%, and further At: 0.05 = 2.0%, zr:
o, os ~20%, V:0.10~0.80%, Co
: 0.50-5.0%, W: 0.50-5.0%, and the remainder is F.
After molding from a cast alloy consisting of e and unavoidable impurities,
A tool material for manufacturing seamless steel pipes that is patented as having been subjected to heat treatment in an oxidizing atmosphere at a temperature range of 900 to 1250°C.