DESC:“METHOD OF COATING PIERCING PLUG IN PIERCING PROCESS IN THE MANUFACTURING OF SEAMLESS STEEL
TUBES”

FIELD OF INVENTION:

This invention relates to a method of manufacturing of seamless steel tubes. More particularly the invention relates to a method of coating the piercing plug in the piercing process.

The present invention involves process of protecting plug with coating for manufacturing of seamless steel tube of all grades and for any other hot piercing process.

BACKGROUND/ PRIOR ART OF THE INVENTION:

Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.

During manufacturing of seamless steel tubes there are several stages starting from billet heating in rotary hearth furnace to cutting the tubes to the required length. The hollow billet is formed in the piercing mill over a plug located between two rolls located in skew angle. The plug is attached at one end of a long mandrel and the other end of the mandrel is fixed on the mandrel thrust block.
The mandrel thrust blocks move back and forth for every piercing operation. The plug is subjected to wear at elevated temperature. The wear rate is high when processing higher alloy steels. Hence, there is a need to find a suitable method of coating the piercing
plug which will improve life.

Some of the manufacturers use ceramic or metal oxide as coating of piercing plugs. This requires special technique and is expensive.

Hence, the present invention has been proposed, which can address the shortcomings of the prior art(s) and serve the purpose
effectively.

OBJECTS OF THE INVENTION:

Primary object of the invention is to provide a method of coating piercing plug in piercing process in the manufacturing of seamless
steel tubes.

Another object of present invention is to propose a method of coating the piercing plug, which overcomes drawbacks of the prior
art(s).

A still further object of present invention is to propose coating of piercing plug through weld deposition.

These and other objects and advantages of the present invention will be apparent to those skilled in the art after a consideration of the following detailed description taken in conjunction with the accompanying drawings in which a preferred form of the present invention is illustrated.

SUMMARY OF THE INVENTION:

One or more drawbacks of conventional systems and process are overcome, and additional advantages are provided through the apparatus/composition and a method as claimed in the present disclosure. Additional features and advantages are realized through the technicalities of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered to be part of the claimed disclosure.

According to this invention, there is provided method of coating piercing plug in piercing process in the manufacturing of seamless steel tubes comprises steps of:

-Machining (Preparation of weld surface),
- Welding of wear resistant material,
-Final machining for finishing to maintain the overall dimensions of piercing plugs.
The welding is carried out by TIG welding up to at least two layers.
The coating of wear resistant material is carried out for a thickness of ? 2 mm.
The wear resistant material is preferably Nickel based material.
The tip of the plug alone is coated about up to one third height where it is critical as high temperature material flow happens in the region.

Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.
It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined to form a further embodiment of the disclosure.
The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:

The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and processes that are consistent with the subject matter as claimed herein, wherein:-

Figure-1 shows: The general cross piercing process in a schematic diagram in accordance with the prior art.

Figure -2 Shows: Plug with weld deposition after wear resistant coating according to the present invention.

The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAIL DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS:

While the embodiments of the disclosure are subject to various modifications and alternative forms, specific embodiment thereof have been shown by way of example in the figures and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.

Reference may be made to Figure illustrating the general cross-section of cross piercing operation in accordance to the prior art. Here, the billet (1) is forced upon the CPE Roll (3) where billet (1) undergoes deformation taking place in Hollow billet (2) when the material passes over plug (4).

The present invention makes a disclosure regarding a technology pertaining to a method of coating piercing plug in piercing process in the manufacturing of seamless steel tubes.

Now referring to Figure -2 Indicating plug with weld deposition after wear resistant coating according to the present invention.

According to the provision in the present invention, figure 2 shows the CPE Plug (1) after wear resistant coating (2) post welding. Before deposition, the CPE plug (1) is machined for about 2 mm and after wear resistant coating (2) finishing machining is carried out.

The surface of the plugs is machined prior to coating for a thickness of about 2 mm, welding by a suitable welding process to a minimum of 2 layers to have machining tolerance of the piercing plugs. Final machining is done to maintain the overall dimensions of piercing plugs.

The steps for method of coating the piercing plug in the piercing process is as follows:
-Machining (Preparation of weld surface),
- Coating for a thickness of about 2 mm,
-Final machining for finishing to maintain the overall dimensions of piercing plugs.
The piercing plugs are coated with high wear and heat resistance material by welding process to improve the life of the piercing plugs.
The welding parameters used for Coating of CPE plug is as follows:

Sl.No Description Value
1. Main Current 120A
2. Voltage 12 -13.5 V
3. Travel Speed 17- 20 cm/min
4. Hotwire current 30A-35A
5. Hot wire feed rate 110-150 cm/min
6. Shielding gas flow rate 18ltr/min

Accordingly, the piercing plug is subjected to TIG welding of wear resistance material. The wear resistant material selected is preferably Nickel based material. The tip of the plug alone is coated about up to one third height where it is critical as high temperature material flow happens in the region.

The coated plug is put to use in the course of actual piercing during higher alloy. When comparing with ceramic oxide plug, the life to cost ratio is high.
ADVANTAGES OF INVENTION

-The improved method of wear resistant weld coating aids in improving plug tip life.

-The coating on the plugs achieves the desired wear and heat resistance, wherein welding process parameters are used for coating on the plugs.

-The tip life is more when compared to uncoated plug,

- Protects plug with coating for manufacturing of seamless steel tube of all grades and for any other hot piercing process.
Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases, it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.

Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.
It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particulars claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogues to “at least one of A, B and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B”.

The above description does not provide specific details of manufacture or design of the various components. Those of skill in the art are familiar with such details, and unless departures from those techniques are set out, techniques, known, related art or later developed designs and materials should be employed. Those in the art are capable of choosing suitable manufacturing and design details.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.

The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.

While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
,CLAIMS:We Claim:

1. Method of coating piercing plug in piercing process in the manufacturing of seamless steel tubes comprises steps of:

-Machining (Preparation of weld surface),
- Coating of wear resistant material (2),
-Final machining for finishing to maintain the overall dimensions of piercing plugs.
2. The method of coating piercing plug in piercing process as claimed in claim 1, wherein the welding parameters used for Coating of CPE plug is as follows:

Sl.No Description Value
1. Main Current 120A
2. Voltage 12 -13.5 V
3. Travel Speed 17- 20 cm/min
4. Hotwire current 30A-35A
5. Hot wire feed rate 110-150 cm/min
6. Shielding gas flow rate 18ltr/min

3. The method of coating piercing plug in piercing process as claimed in claim 1 or 2, wherein the welding is carried out by TIG welding up to at least two layers.
4. The method of coating piercing plug in piercing process as claimed in claims 1-3, wherein the coating of wear resistant material is carried out for a thickness of ? 2 mm.
5. The method of coating piercing plug in piercing process as claimed in claim 4, wherein the wear resistant material is preferably Nickel based material.
6. The method of coating piercing plug in piercing process as claimed in claims 1- 5, wherein the tip of the plug alone is coated about up to one third height where it is critical as high temperature material flow happens in the region.