JPS6293362A

JPS6293362A - Manufacture of tool for pipe making

Info

Publication number: JPS6293362A
Application number: JP23223685A
Authority: JP
Inventors: Mitsuhiko So; 宗　光彦; Yoshihisa Kato; 喜久加藤
Original assignee: Daido Steel Co Ltd
Current assignee: Daido Steel Co Ltd
Priority date: 1985-10-17
Filing date: 1985-10-17
Publication date: 1987-04-28

Abstract

PURPOSE:To manufacture tool for pipe making having a high durability, by melting surface of tool material made of metal by plasma transfer arc of carrier gas composed of oxidizing gas and inert gas to form oxide protecting layer. CONSTITUTION:Surface of tool material made of metal for pipe making is melted by plasma transfer arc using carrier gas composed of oxidizing gas or nitriding gas and the balance inert gas, to form protecting layer made of oxide or nitride on the surface. In case protecting layer of oxide is formed, gaseous mixture composed of 0.1-10vol% O2 or 0.3-30vol% CO2 and the balance Ar is used as carrier gas. In case protecting layer of nitride is formed, gaseous mixture composed of 1-30vol% N2 and the balance Ar is used as carrier gas. In this way, durable protecting layer is formed and tool for pipe making having a prolonged service life is manufactured.

Description

[Detailed description of the invention]

ル町匹は的［産業上の利用分野］本発明は製管用工具、とくにプラグの製造方法に関する
。TECHNICAL FIELD The present invention relates to a method for manufacturing pipe-making tools, particularly plugs.

[Conventional technology]

継目無鋼管の製造に使用するガイドシコー、プラグなど
の工具は、高温下に強い衝撃を受（）るので、表面は高
い耐摩耗性と耐焼付性をもっことを要求される。 ■貝の素材とする金属は、低合金鋼、ステンレス工具鋼
、耐熱鋼、Ｎｉ基超超合金るいはＣｏ基超超合金ど、加
工の対象に応じて多種にわたるが、最も一般的には、０
．３Ｇ−０，４Ｓｔ　−０，６Ｍｎ　−３Ｃｒ−１Ｎｉ
−Ｆｅの組成を有するる材料を用い、この表面に耐摩耗
性および耐焼付↑４を与える目的で、スチーミングを行
なう。　スチーミングは、成形した工具素材を、代表的
には９２０”Ｇで６時間にわたってスチームで処理し、
表面に厚さ１５０〜３ＣＯμの酸化物のスケール層を形
成させる。　酸化物スケールは、その厚さが厚いほど、
また強固に工具表面に固着しているほど、工具寿命が長
い。たとえば、２５０〜３ＣＯμの厚さがあれば、プラ
グとしてステンレス鋼造管用素材２５〜３５本を穿孔で
きるが、１５０μ程度では７〜８本で寿命がくる。　こ
れは、表面のスケール層が消費し尽されるからである。このようなわけで、従来のスチーミングによる酸化物ス
ケールの生成は、工具表面の強化手段としてはなお十分
に満足できるものではない。Tools used in the manufacture of seamless steel pipes, such as guides and plugs, are subjected to strong impacts at high temperatures, so their surfaces must have high wear resistance and seizure resistance. ■There are many types of metals that shells are made from, depending on the object of processing, such as low alloy steel, stainless tool steel, heat-resistant steel, Ni-based super-alloy, or Co-based super-alloy, but the most common ones are: 0
．． 3G-0,4St-0,6Mn-3Cr-1Ni
Using a material having a composition of -Fe, steaming is performed for the purpose of imparting wear resistance and seizure resistance ↑4 to the surface. Steaming involves treating the formed tool stock with steam, typically at 920"G, for 6 hours.
An oxide scale layer with a thickness of 150 to 3 COμ is formed on the surface. The thicker the oxide scale, the more
Also, the stronger the bond to the tool surface, the longer the tool life. For example, if the thickness is 250 to 3 COμ, 25 to 35 pieces of stainless steel pipe material can be punched as plugs, but if the plug is about 150μ, the life span will be reached after 7 to 8 pieces. This is because the surface scale layer is consumed. For this reason, the generation of oxide scale by conventional steaming is still not fully satisfactory as a tool surface strengthening means.

[Problems to be solved by the invention]

本発明の目的は、製管用工具、とくにプラグの製造に当
って、耐久性のある表面保護層を形成し、いっそう延長
された工具寿命を有する製管用工具を製造する方法を（
？供することにある。及団少講虞【問題点を解決するための手段］本発明の製管工具の製造方法は、製管用の金属製工具素
材の表面を、酸化性ガスまたは窒化性ガスを含有し、残
りが不活性ガスからなるキャリアガスを用いたプラズマ
トランスファーアーク（以下、ｒＰＴＡＪという）によ
り溶解し、表面に酸化物または窒化物からなる保護層を
形成させることを特徴とする。酸化物の保護層を形成させようとする場合は、キャリア
ガスとして、０．１〜１０％（容積％）の０２または０
．３〜３０％のＣＯ２を含有し、残部がＡｒである混合
ガスを使用するとよい。一方、窒化物の保護層を形成させようとする場合は、キ
ャリアガスとして、１〜３０％のＮ２を含有し、残部が
Ａｒである混合ガスを使用するとよい。酸化物保護層の主成分はＦｅＯであるが、工具素材の金
属が鋼合金でなくＮｉ基やＣＯ基の合金である場合、表
面の酸化によるＦｅＯの生成が少ないから、キャリアガ
ス中に酸化性ガスを混合するとともにＦｅ粉末を供給し
、ＦｅＯを生成させることが好ましい。本発明の推奨すべき態様は、上記したいずれかの方法に
従って工具表面に酸化物層または窒化物−〇　− 層を形成さゼたのｔ５、：１−Ｖリアガスとして不活ｆ
ノ１ガスを使用したｌ）Ｔ　Ａによる再溶解を行なうも
のである。［作　用］本発明に従つ−Ｃ−［−真表面のＰＴＡ溶解を行イＴえ
ば、表面に酸化物また（よ窒化物の層が生成し、保護お
よび潤滑作用をする。　両者のはたらきは若干異なり、
酸化物（，１従来のスチーミングをした１′具の場合と
同様であるが、窒化物はその硬さにより耐摩耗ｆ］１と
耐焼飼↑’Ｉをｅｊえるしのと考えられる。事実、窒化物は酸化物にくらべて薄い層しかできないが
、それで有効である。ＰＴＡにより生成した保護層は、酸化物−し窒化物も、
その粒子が微細であつ°ＵＩ貝表面表面融したマトリク
ス中に固定されていて容易に剥落しく【いから、従来得
られていたものよりも耐久１ノ１が高い。　とくに、前
記した推奨Ｊべき態様に従って、不活性ガスだ（）をキ
ャリアガスとした再溶解を行なった場合には、■［真表
面が溶解して表面が平滑となり、再結晶するときにさら
に微細な組織となるとともに工具表面により固着するか
ら、保護層の耐久↑）１が増し、工具寿命の延長にすこ
ぶる効果がある。［実施例１］０．３Ｇ　−０，４Ｓｉ−０，６Ｍｎ　−３Ｃｒ　−１
Ｎｉ−［ｅの組成をもつ鋼を鍛造して、長さ４ＣＯｍ、
直径２１４順の穿孔プラグ素材をつくった。０２：１．２％を含有し、残部がＡｒである混合ガスを
キャリアガスとして用い、」−記プラグ素材の造管用材
料に接触する表面に対してＰＴＡ溶解を行なった。ＦｅＯを主成分とする酸化物層が、平均１５ＣＯｉｌの
厚さに生成していた。このプラグは、ステンレス調造管用材料の加工本数が６
５本に達した。［実施例２］０．３（、−５Ｏｒ　−ＩＭＯ−０，１５Ａｊ！−ＦＢ
の組成をもつ鋼で、実施例１と同じサイズの穿孔プラグ
素材をつくった。Ｎ２：１０％を含有し残部がＡｒである混合ガスを用い
、ＰＴＡ溶解を行′／、ｆつだ。Ｃｒ　２　Ｎ、Ａｊ’　Ｎなどの窒化物層が表面をおお
ったプラグが冑られ、ぞの加工可能本数ＬＬ　５０本で
あった。［実施例３］組成が０．０３　Ｃ−１６Ｃｒ　−１６Ｍｏ　−３Ｆｅ
　−Ｎ１のＮｉ基超超合金月利とする、実施例１と同じ
サイズの穿孔プラグ素材に対して、ＣＯ２：２゜０％を
含有し、残部がＡｒである混合ガスをキレリアガスとす
るＰＴＡ溶解を行なった。　このとき、粒［１５０メツ
シユ以下のＦｅ粉末をキャリアガス中に供給した。ＦｅＯを主成分とする酸化物が、工具表面に生成した。このプラグ【；１、実施例１と加工本数が同様であった
。【実施例４］実施例１で得たプラグの表面を、Ａｒガスだけをキャリ
アガスとするＰＴＡ再溶解を行なった。表面は平滑になり、より微細な酸化物がマトリウス中に
固定されたプラグが得られた。この工具により穿孔できた造管用素材は、７６本にのぼ
った。Ｒ班の激ヌ本発明の方法により製造した製管用工具は、その表面の
保護層の耐久↑ノ１が高いから、苛酷な使用条件によく
耐え、従来品より改善された寿命を示す。　プラグの場
合、従来のスチーミングによる酸化物スケール生成を行
なったものにくらべ、加工可能本数が確実に増大する。しかも、ＰＴＡ溶解はスチーミングより短時間で完了す
るから、工具製造のコストは引き下げることができる。　上記した寿命の延長とあいまって、継目無鋼管などの
製造コストの低減に寄与する。The object of the present invention is to provide a method for manufacturing pipe-making tools, especially plugs, by forming a durable surface protective layer and having a longer tool life.
? It is about providing. [Means for Solving the Problems] The method for manufacturing a pipe making tool of the present invention is such that the surface of a metal tool material for pipe making is coated with an oxidizing gas or a nitriding gas, and the remainder is It is characterized in that it is melted by plasma transfer arc (hereinafter referred to as rPTAJ) using a carrier gas made of an inert gas, and a protective layer made of oxide or nitride is formed on the surface. When attempting to form a protective layer of oxide, use 0.1 to 10% (volume %) of 02 or 0 as a carrier gas.
．． It is preferable to use a gas mixture containing 3 to 30% CO2 and the balance being Ar. On the other hand, when a nitride protective layer is to be formed, a mixed gas containing 1 to 30% N2 and the balance Ar is preferably used as the carrier gas. The main component of the oxide protective layer is FeO, but if the metal of the tool material is not a steel alloy but a Ni-based or CO-based alloy, less FeO is generated due to surface oxidation, so there is no oxidizing effect in the carrier gas. It is preferable to mix gas and supply Fe powder to generate FeO. A preferred embodiment of the present invention is to form an oxide layer or a nitride layer on the tool surface according to any of the methods described above.
1) Re-dissolution by TA using No. 1 gas is carried out. [Function] When PTA is melted on the true surface according to the present invention, an oxide or nitride layer is formed on the surface and has a protective and lubricating effect. is slightly different,
Oxide (1) is the same as in the case of conventional steamed tools, but nitride is thought to have higher wear resistance and burn resistance due to its hardness.Fact Although nitrides form only thinner layers than oxides, they are still effective.The protective layer produced by PTA is
The particles are fine and are fixed in the molten matrix on the surface of the UI shell, so they are easily peeled off and therefore have higher durability than those previously available. In particular, when remelting is performed using an inert gas () as a carrier gas in accordance with the above-mentioned recommended method, As the protective layer becomes more durable and adheres to the tool surface, it increases the durability of the protective layer and has a great effect on extending tool life. [Example 1] 0.3G -0,4Si-0,6Mn -3Cr -1
Forged steel with a composition of Ni-[e, length 4 COm,
A perforated plug material with a diameter of 214 was made. Using a mixed gas containing 0.02:1.2% and the balance being Ar as a carrier gas, PTA was dissolved on the surface of the plug material in contact with the pipe-making material. An oxide layer containing FeO as a main component was formed to an average thickness of 15 COil. This plug can process 6 pieces of stainless steel pipe material.
It reached 5 pieces. [Example 2] 0.3(,-5Or-IMO-0,15Aj!-FB
A perforated plug material of the same size as in Example 1 was made from steel having the composition. PTA was dissolved using a mixed gas containing 10% N2 and the balance being Ar. The plugs whose surfaces were covered with a nitride layer of Cr 2 N, Aj' N, etc. were removed, and the number of plugs that could be processed was LL 50. [Example 3] Composition is 0.03 C-16Cr-16Mo-3Fe
- PTA melting using Kyrelia gas as a mixed gas containing 2.0% CO2 and the balance being Ar for a perforated plug material of the same size as in Example 1 with a monthly yield of Ni-based superalloy of N1. I did it. At this time, Fe powder grains [150 mesh or less] were supplied into the carrier gas. An oxide mainly composed of FeO was generated on the tool surface. This plug [;1, the number of processed pieces was the same as in Example 1. [Example 4] The surface of the plug obtained in Example 1 was subjected to PTA remelting using only Ar gas as a carrier gas. The surface became smooth and a plug with finer oxides fixed in the matrix was obtained. A total of 76 tube-making materials were drilled using this tool. The pipe-making tool manufactured by the method of the present invention has a protective layer on its surface that has high durability, so it can withstand harsh conditions of use and has an improved lifespan compared to conventional products. In the case of plugs, the number of plugs that can be processed is definitely increased compared to those in which oxide scale is generated by conventional steaming. Furthermore, since PTA melting can be completed in a shorter time than steaming, tool manufacturing costs can be reduced. Combined with the above-described extension of life, this contributes to reducing manufacturing costs of seamless steel pipes and the like.

Claims

[Claims]

(1) The surface of a metal tool material for pipe making is melted using a plasma transfer arc using a carrier gas containing an oxidizing gas or a nitriding gas, with the remainder being an inert gas, and the surface is coated with oxides or nitrides. A method for manufacturing a pipe-making tool, which comprises forming a protective layer consisting of:

(2) The metal constituting the tool is selected from low alloy steel containing 1% or more of Cr, stainless tool steel, heat-resistant steel, Ni-based superalloy, and Co-based superalloy. Manufacturing method of Section 1.

(3) As carrier gas, 0.1 to 10% (volume%)
The manufacturing method according to claim 1, wherein the oxide protective layer is formed using a mixed gas containing 0.3 to 30% of O_2 or 0.3 to 30% of CO_2 and the balance being Ar.

(4) The manufacturing method according to claim 1, in which a nitride protective layer is formed using a mixed gas containing 1 to 30% of N_2 and the balance being Ar as a carrier gas.

(5) Ni-based superalloy or C as the metal constituting the tool
Claim 1: Using an o-base superalloy, mixing an oxidizing gas into the carrier gas of the plasma transfer arc and supplying Fe powder, forming a protective layer of Fe oxide on the tool surface. Manufacturing method of section.

(6) After forming a protective layer of oxide or nitride on the surface, remelting is performed using a plasma transfer arc using an inert gas as a carrier gas to refine the oxide or nitride particles. The manufacturing method according to claim 1, which includes the step of strengthening the adhesion to the tool surface.

(7) The manufacturing method according to any one of claims 1 to 6, wherein the pipe-making tool is a plug.