CLIAMS:We Claim :

1. Wire rod steel with improved drawability comprising :
C-0.07-0.15 % by wt. prerefably 0.07 -0.09 % by wt;
Mn-1.4 – 1.85 % by wt. preferably 1.4 -1.5 % by wt;
S- Upto 0.025 % by wt. preferably less than 0.010 % by wt;
P- Upto 0.025% by wt. preferably less than 0.015 % by wt;
Si-0.8 to 1.15 % by wt. preferably in the range of 0.8 -0.9 % by wt.;
Ca- Upto 0.0010 % by wt. preferably less than 0.0008% by wt;
N-Upto 0.0050 % by wt. preferably less than 0.004 % by wt ;and
balance being Fe.

2. Wire rod steel with improved drawability as claimed in claim 1 having reduced UTS of less than 500 MPa and sufficiently high YS at least 370 MPa.

3. Wire rod steel with improved drawability as claimed in anyone of claim 1 or 2 comprising

rod having thickness : 5 to 6 preferably about 5.5 mm having
Yield Strength : 340 – 370 MPa;
UTS : 475 – 500 MPa;
% Elongation : 41 – 42;
Ra : 82 – 85 %.

4. Wire rod steel with improved drawability as claimed in anyone of claims 1 to 3 having Pearlite microstructure.

5. A process for the manufacture of wire rod steel with improved drawability as claimed in anyone of claims 1 to 4comprising:

(i) selectively providing alloying elements in said steel making comprising
C-0.07-0.09 % by wt.;
Mn-1.4 – 1.5 % by wt.;
S- Upto 0.25 % by wt.;
P- Upto 0.025% by wt;
Si-0.8 to 0.9 % by wt.;
Ca- Upto 0.0010 % by wt.;
N-Upto 0.0050 % by wt.;and
balance being Fe.
(ii) continuous billet casting;
(iii) re-heating,
(iv) wire rod rolling ; and
(v) controlled retarded cooling such as to achieve reduced UTS of less than 500 MPa and sufficiently high YS at least 370 MPa for desired drawability .

6. A process for the manufacture of wire rod steel as claimed in claim 5 wherein the
said alloying elements are selectively involved to achieve desired drawability including for making thin (<1 mm) welding electrodes.

7. A process as claimed in anyone of claims 4 to 6 comprising maintaining operating parameters involving:
Furnace Temperature (Soaking) in the temperature range of 1080 – 1120 oC;
Laying Head Temperature in the range of 910 to 940 oC preferably about 920 oC;
Finish Rolling Temperature < 250 oC;
Controlled cooling involving full retarded cooling.

8. A process as claimed in anyone of claims 4 to 7 wherein said controlled retarded cooling involves retarded cooling in stelmor by closing the stelmor cover such as to obtain desired microstructure.
9. A process as claimed in anyone of claims 4 to 7 which is carried out involving thicker billets (165 x 165 mm) and is free of involvement of any ferroalloys.
10. Thin welding electrodes obtained of wire rod steel having alloying elements comprising of :

C-0.07-0.15 % by wt. prerefably 0.07 -0.09 % by wt;
Mn-1.4 – 1.85 % by wt. preferably 1.4 -1.5 % by wt;
S- Upto 0.025 % by wt. preferably less than 0.010 % by wt;
P- Upto 0.025% by wt. preferably less than 0.015 % by wt;
Si-0.8 to 1.15 % by wt. preferably in the range of 0.8 -0.9 % by wt.;
Ca- Upto 0.0010 % by wt. preferably less than 0.0008% by wt;
N-Upto 0.0050 % by wt. preferably less than 0.004 % by wt ; and
balance being Fe.

11. Thin welding electrodes as claimed in claim 10 having thickness in the range of 1 mm - 0.7 mm preferably < 1 mm.

12. Thin welding electrodes as claimed in anyone of claims 10 or 11 suitable for shielded welding having YS, MPa in the range of 340 to 370 preferably about 360 and UTS, MPa in the range of 475 to 500 preferably about 480.

Dated this the 3rd day of January, 2014
Anjan Sen
Of Anjan Sen & Associates
(Applicants Agent)
,TagSPECI:FIELD OF THE INVENTION

The present invention relates to wire rod steel with improved drawability for producing thin welding electrodes and a process for its production. More particularly, the present invention is directed to providing a simple composition of wire rod steel with improved drawability of wire rod steel with low carbon and low manganese made through retarded cooling in stelmor which can be directly used for manufacturing thin welding electrodes(<1 mm) for advantageous application in MIG welding of thin sheets. Importantly, in the present process for producing the steel grade with improved drawability slow cooling of low carbon steel is implemented by adoption of controlled cooling to have optimum microstructural combination of pearlitic core resulting in sufficiently high YS. The developed grade has lower UTS but sufficiently high YS to match the requirements of high reduction during electrode drawing and for its application in welding simultaneously.

BACKGROUND OF THE INVENTION

It is well known in welding consumable manufacturing industry, that core wire of coated electrodes as well as bare wire electrodes are drawn from wire rods of higher section in wire drawing machine. There are many varieties of welding electrodes, depending on the welding material and welding process. Electrodes are made to deal with a specific kind and range of electrical current and come with different coatings and in different sizes depending on the welding requirements. Electrodes are manufactured using a standard 5.5 mm wire rod by subjecting it to wire drawing machine, where electrodes of various sizes are drawn. Each 5.5 mm wire rod coil piece is loaded into a powerful hydraulic press that squeezes the wire through a narrow opening, converting it into a long, narrow fiber. This fiber is secured to a machine called a "drawer" which tightly winds it as the press squeezes it out. The tension shrinks the cross section even further, resulting in a giant coil of wire-thin steel. This thin wire is used as welding electrode. The most common size is 1.2 mm in diameter. The welding electrode is directed by a wire feeder toward the welding operation in the form of a continuous wire fed through a welding torch cable from a wire supply, and an arc is generated at the torch between the end of the electrode and the work piece for melting and depositing electrode material to a weld in a controlled fashion. Many arc welding processes, such as metal inert gas (MIG) techniques, employ an external inert shielding gas such as argon around the welding arc to inhibit oxidation or nitridation of the molten metal.
In modern manufacturing processes, the requirement of welding of thinner sheets is increasing and subsequently the demand for thinner electrodes (< 1 mm and preferably 0.8 mm). The process of drawing 0.8 mm thin wires from a 5.5 mm wire rod requires material to be softer or with high drawability in addition to sufficient strength for its welding application.
There has been therefore a need in the art to developing wire rod grade of steel with improved drawability which would have lower UTS but sufficiently high YS to match the requirements of high reduction during electrode drawing and its application in welding simultaneously.

OBJECTS OF THE INVENTION

The basic object of the present invention is thus directed to providing a wire rod steel grade with improved drawability suitable for producing thin (<1 mm) welding electrodes by wire drawing for advantageous application in MIG welding of thin sheets and a cost effective process for production of such steel grade.
A further object of the present invention is directed to providing a wire rod steel with improved drawability involving wire rod steel composition having low carbon and controlled cooling such as to improve drawability which can be directly used for manufacturing thin welding electrodes.
A still further object of the present invention is directed to providing a wire rod steel with improved drawability wherein reduction in carbon and manganese content is maintained to soften the material leading to reducing the mechanical properties specifically UTS to have better drawability.

A still further object of the present invention is directed to providing a wire rod steel with improved drawability wherein the developed grade has lower UTS but sufficiently high YS to match the requirements of high reduction during electrode drawing and its application in welding simultaneously.
A still further object of the present invention is directed to providing a wire rod steel with improved drawability wherein wire rod grade can be made even from high thicker billets (165 x 165 mm) rolling it in the same mill, which otherwise would not have been possible with higher carbon as used in similar grade of steel.

A still further object of the present invention is directed to providing a wire rod steel with improved drawability wherein thicker billet in turn increase the coil weight and therefore resulting in longer welding operation from single coil.

A still further object of the present invention is directed to providing a wire rod steel with improved drawability wherein the cost of production of the new grade steel is kept minimum due to no usage of any ferroalloys.

SUMMARY OF THE INVENTION

The basic aspect of the present invention is thus directed to providing Wire rod steel with improved drawability comprising:
C-0.07-0.15 % by wt. preferably 0.07 -0.09 % by wt;
Mn-1.4 – 1.85 % by wt. preferably 1.4 -1.5 % by wt;
S- Upto 0.025 % by wt. preferably less than 0.010 % by wt;
P- Upto 0.025% by wt. preferably less than 0.015 % by wt;
Si-0.8 to 1.15 % by wt. preferably in the range of 0.8 -0.9 % by wt.;
Ca- Upto 0.0010 % by wt. preferably less than 0.0008% by wt;
N-Upto 0.0050 % by wt. preferably less than 0.004 % by wt ; and
balance being Fe.

A further aspect of the present invention is directed to said wire rod steel with improved drawability having reduced UTS of less than 500 MPa and sufficiently high YS at least 340 MPa.

A still further aspect of the present invention is directed to said wire rod steel with improved drawability comprising

rod having thickness : 5 to 6 mm preferably about 5.5 mm having
Yield Strength : 340 – 370 MPa;
UTS : 475 – 500 MPa;
% Elongation : 41 – 42;
Ra : 82 – 85 %.

A further aspect of the present invention is directed to said wire rod steel with improved drawability having Pearlite microstructure.

Yet another aspect of the present invention is directed to a process for the manufacture of wire rod steel with improved drawability as described above comprising:

(i) selectively providing alloying elements in said steel making comprising
C-0.07-0.09 % by wt.;
Mn-1.4 – 1.5 % by wt.;
S- Upto 0.25 % by wt.;
P- Upto 0.025% by wt;
Si-0.8 to 0.9 % by wt.;
Ca- Upto 0.0010 % by wt.;
N-Upto 0.0050 % by wt.; and
balance being Fe.
(ii) continuous billet casting;
(iii) re-heating,
(iv) wire rod rolling ; and
(v) controlled retarded cooling such as to achieve reduced UTS of less than 500 MPa and sufficiently high YS atleast 370 MPa for desired drawability .

A further aspect of the present invention is directed to said process for the manufacture of wire rod steel wherein the said alloying elements are selectively involved to achieve desired drawability including for making thin (<1 mm) welding electrodes.

A still further aspect of the present invention is directed to said process comprising maintaining operating parameters involving:
Furnace Temperature (Soaking) in the temperature range of 1080 – 1120 oC;
Laying Head Temperature in the range of 900 to 940oC preferably about 920 oC;
Finish Rolling Temperature < 250oC;
Controlled cooling involving full retarded cooling.
Yet another aspect of the present invention is directed to said process wherein said controlled retarded cooling involves retarded cooling in stelmor by closing the stelmor cover such as to obtain desired microstructure.

A still further aspect of the present invention is directed to said process which is carried out involving thicker billets (165 x 165 mm) and is free of involvement of any ferroalloys.
A further aspect of the present invention is directed to thin welding electrodes obtained of wire rod steel having alloying elements comprising of:

C-0.07-0.15 % by wt. prerefably 0.07 -0.09 % by wt;
Mn-1.4 – 1.85 % by wt. preferably 1.4 -1.5 % by wt;
S- Upto 0.025 % by wt. preferably less than 0.010 % by wt;
P- Upto 0.025% by wt. preferably less than 0.015 % by wt;
Si-0.8 to 1.15 % by wt. preferably in the range of 0.8 -0.9 % by wt.;
Ca- Upto 0.0010 % by wt. preferably less than 0.0008% by wt;
N-Upto 0.0050 % by wt. preferably less than 0.004 % by wt ; and
balance being Fe.

A still further aspect of the present invention is directed to said thin welding electrodes having thickness in the range of 1 mm - 0.7 mm preferably 0.8 mm.
A further aspect of the present invention is directed to said thin welding electrodes suitable for shielded welding having YS, MPa in the range of 340 to 370 preferably about 360 and UTS, MPa in the range of 475 to 500 preferably about 480.

The objects and advantages of the present invention are described hereunder in greater details with reference to non limiting illustrative embodiments.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Figure 1: is the flow chart showing the steps involved in the process for the manufacture of wire rod steel with improved drawability according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWING
The present invention relates to a wire rod steel grade with improved drawability suitable for producing thin (<1 mm) welding electrodes by wire drawing for advantageous application in MIG welding of thin sheets and a cost effective process for production of such steel grade.
In modern manufacturing processes, the requirement of welding of thinner sheets is increasing and consequently the demand for thinner electrodes (< 1 mm and preferably 0.8 mm). The process of drawing 0.8 mm thin wires from a 5.5 mm wire rod requires material to be softer or with high drawability in addition to sufficient strength for its welding application.
The present invention thus provides a new grade of steel with reduced carbon (0.05 – 0.08 %), reduced manganese (1.4 – 1.5 %) and adoption of an innovative fully retarded cooling in stelmor during rolling resulting in improved drawability. The reduction in carbon and manganese was to soften the material leading to reducing the mechanical properties specifically UTS. UTS were reduced from 530 MPa (in similar grade) to less than 500 MPa in the new grade to have better drawability. Stelmor cooling is forced air cooling process where the cooling bed is generally used for a cooling the rolled wire rod. The strength and ductility of high carbon steel wire rods are controlled online during rolling with this process. In the present invention, low carbon steel requires slow cooling to achieve the desired properties. Adoption of full retarded stelmor cooling by covering the stelmor cover was to achieve slow cooling to have optimum microstructural combination of pearlitic core resulting in sufficiently high YS. The new developed grade has lower UTS but sufficiently high YS to match the requirements of high reduction during electrode drawing and its welding simultaneously. This new combination also allows the steel maker to use a larger billet size (165 x165 mm) leading to a higher coil weight for prolonged welding operation, as compared to general billet size (135 x 135 mm).

The new wire rod grade steel with improved drawability for producing thin (<1 mm) welding electrodes produced according to the present invention has the selective chemical composition as given in following Table I:
Table I:

%-C %-Mn %-S max. %-P max. %-Si max %-Ca max %-N, max.
0.07- 0.09 1.4 – 1.5 0.025 0.025 0.8 – 0.9 0.0010 0.0050

While deciding on the selective composition of the wire rod steel to achieve improved drawability, desired microstructure and combination of mechanical properties, following considerations were taken into account:

C: 0.07 % or more and less than 0.15% by weight

Carbon is an element that gives the strength and hardness to steel. The carbon content needs to be 0.07% or more to ensure a required strength and hardness for electrode drawing. At a C content of 0.15% or more, steel becomes hard and requires high loads for drawing. Accordingly, the C content is 0.07% or more and less than 0.15% and preferably in a range of 0.07 to 0.09% by weight.

Si: 0.8% or more and less than 1.15% by weight

Si is added as de-oxidiser and acts to reinforce steel, and a necessary amount of Si is added to steel in accordance with the intended strength of the steel and needs to be contained in an amount of 0.8% or more. Incorporation of excess Si exceeding 1.15% significantly deteriorates drawability. Accordingly, the Si content is 0.8% or more and 1.15% or less and is preferably in a range of 0.8 to 0.9% by weight.

Mn: 1.4% or more and 1.85% or less by weight

Manganese is an element that improves the strength of steel material and 1.4% or more of Mn needs to be contained to ensure a required strength. In contrast, the drawability is deteriorated if Mn is contained exceeding 1.85%. Accordingly, the Mn content is 1.4% or more and 1.85% or less and preferably in a range of 1.4 to 1.5% by weight.

P: 0.025% or less by weight

Phosphorus is an element that improves the atmospheric corrosion resistance of the structural steel material. However, adding too much P to steel in an amount of larger than 0.025 % by weight will have some negative influences on the desired strength of the steel wires. Accordingly, the P content is 0.025% or less and preferably less than 0.015% by weight.

S: 0.020% or less by weight

At a sulfur content exceeding 0.020%, strength of drawn steel is deteriorated. Accordingly, the S content is restricted to 0.020% or less and preferably less than 0.010% by weight.

N: not larger than 0.005 % by weight

More desirably, N should be as lesser as possible for better mechanical properties of the steel. N in steel in an amount of not larger than 0.005 % by weight, would not have any significant negative influences on the hardenability and other properties of the steel. Therefore, the N content of steel is defined to be not larger than 0.005 % by weight, but preferably smaller than 0.004 % by weight.

Ca: not larger than 0.001 % by weight

Calcium is added for steel cleanliness and improvement in electrode weldability. Addition of higher calcium larger than 0.001% has negative impact on the applications. Accordingly, the Ca content is 0.001% or less and preferably less than 0.0008% by weight.

The balance is Fe and unavoidable impurities.

This new steel grade is made through converter steel making and ladle heating furnace. It is further cast into billets through continuous casting process. These billets are processed through re-heating furnace and hot wire rod rolling followed by controlled cooling. The hot rolled wire rods are inspected manually. Samples are collected from the coils. These samples are tested in laboratory for cleanliness of steel and mechanical properties.

Thus the wire rod steel with improved drawability having above composition has been produced using the following process rout in sequence:
(i) Steel making by LD Converter
(ii) Secondary steel making: Ladle Heating Furnace.
(iii) Continuous billet casting into (165 x 165 mm)
(iv) Re-heating, wire rod rolling, controlled cooling and Coiling with set optimum processing parameters.

Accompanying Figure 1 is the flow chart showing the steps involved in the process for the manufacture of wire rod steel with improved drawability according to the present invention.

The process for the manufacture of wire rod steel with improved drawability according to the present invention comprised the steps of:
(i) selectively involving alloying elements in said steel making comprising (a) Primary Steel Making involving Blowing in LD converter and tapping into steel ladles and (b) Secondary Steel Making involving Alloying addition, composition and temperature control to obtain the composition as given above;
(ii) continuous billet casting;
(iii) re-heating of billets by hot charging directly into re-heating furnace followed by rough rolling;,
(iv) wire rod rolling ; and
(v) controlled retarded cooling and coiling.

In the above process, Wire rod rolling parameters specified for processing are as given in following Table 2:
Table 2:
1 Furnace Temperature (Soaking) 1080 – 1120 oC
2 Laying Head Temperature 920 oC
3 Finish Rolling Temperature < 250 oC
4 Controlled cooling Full Retarded cooling by closing the stelmor cover

Also in the above process, adoption of full retarded stelmor cooling by covering the stelmor cover was to achieve slow cooling to have optimum microstructural combination of pearlitic core resulting in sufficiently high YS
The wire rod steel coils obtained by the process is having rod thickness of 5.5mm and is having pearlitic core.
Samples are collected from the coils. These samples are tested in laboratory for cleanliness of steel and mechanical properties.
Mechanical tests and Metallography

The tensile properties (yield strength, ultimate tensile strength) are measured using 600 mm long test specimens with 50 mm gauge length, on a universal testing machine. All tests are performed at room temperature.

Metallographic analysis is carried out rate the cleanliness of steel. Metallographic samples prepared are polished and etched with 5% nital. A simple light optical microscope is used to record the core and outer microstructure comprising the material.

The wire rod steel with improved drawability produced following the above process are having the following mechanical properties:
Yield Strength :340 – 370 MPa;

UTS : 475 – 500 MPa;

% Elongation : 41 – 42;

Ra : 82 – 85 %.

The rod is having pearlitic microstructure.
Reduction in UTS and improvements in Ra value in the new grade in comparison to similar category old grade as observed through various trials are as shown in the following table 3.

Table 3:
%-C %-Mn %-S max. %-P max. %-Si max %-Ca max %-N, max. YS UTS Ra Remarks
0.08 1.45 0.01 0.01 0.85 0.0005 0.0045 360 480 85 Invention
0.07 1.48 0.01 0.009 0.87 0.0008 0.0048 355 478 84 Invention
0.14 1.42 0.012 0.008 0.85 0.0007 0.007 380 520 78 Comparison
0.12 1.55 0.01 0.009 0.83 0.0008 0.006 375 530 75 Comparison
0.11 1.38 0.009 0.009 0.82 0.0006 0.008 385 535 76 Comparison

It is thus possible by way of the present invention to providing a wire rod steel grade with improved drawability for producing thin (<1mm)electrode wire by wire drawing with required strength and weldability properties. The new developed grade has lower UTS but sufficiently high YS to match the requirements of high reduction during electrode drawing and its application in welding simultaneously. This new combination also allows the steel maker to use a larger billet size (165 x165 mm) leading to a higher coil weight for prolonged welding operation, as compared to general billet size (135 x 135 mm). It is thus possible to ensure the following advantageous features by the present invention:
1. The new wire rod steel with low carbon and low manganese in made through retarded cooling in stelmor can be directly used for manufacturing thin welding electrodes (0.7 - 1 mm).
2. Reduction in UTS and improvement in ‘reduction in area’ in the new grade in comparison to similar category old grade is As shown below
Old Grade New Grade
YS, MPa 370 360
UTS, MPa 530 480
Reduction in Area 75 – 78 % 82 – 85 %

3. Higher possible reduction in area makes it a suitable material for manufacturing thin wires.

4. Adoption of full retarded stelmor cooling by covering the stelmor cover to achieve slow cooling resulted in optimum microstructure.
5. The new wire rod grade can be made even from high thicker billets (165 x 165 mm) rolling it in the same mill, which other wise would not have been possible with higher carbon as used in similar grade of steel.
6. Use of thicker billet in turn increase the coil weight and therefore resulting in longer welding operation from single coil.
7. The new wire rod grade steel reduced the manufacturing defects in welding electrodes.
8. Optimum chemistry of the steel resulted in consistent and favourable mechanical properties suitable for thin welding electrodes
9. Microstructure of the newly developed steel helped maintaining a favourable combination of mechanical properties.
10. Due to no usage of any ferroalloys, the cost of production of the new grade steel is kept minimum.

We Claim :

1. Wire rod steel with improved drawability comprising :
C-0.07-0.15 % by wt. prerefably 0.07 -0.09 % by wt;
Mn-1.4 – 1.85 % by wt. preferably 1.4 -1.5 % by wt;
S- Upto 0.025 % by wt. preferably less than 0.010 % by wt;
P- Upto 0.025% by wt. preferably less than 0.015 % by wt;
Si-0.8 to 1.15 % by wt. preferably in the range of 0.8 -0.9 % by wt.;
Ca- Upto 0.0010 % by wt. preferably less than 0.0008% by wt;
N-Upto 0.0050 % by wt. preferably less than 0.004 % by wt ;and
balance being Fe.

2. Wire rod steel with improved drawability as claimed in claim 1 having reduced UTS of less than 500 MPa and sufficiently high YS at least 370 MPa.

3. Wire rod steel with improved drawability as claimed in anyone of claim 1 or 2 comprising

rod having thickness : 5 to 6 preferably about 5.5 mm having
Yield Strength : 340 – 370 MPa;
UTS : 475 – 500 MPa;
% Elongation : 41 – 42;
Ra : 82 – 85 %.

4. Wire rod steel with improved drawability as claimed in anyone of claims 1 to 3 having Pearlite microstructure.

5. A process for the manufacture of wire rod steel with improved drawability as claimed in anyone of claims 1 to 4comprising:

(i) selectively providing alloying elements in said steel making comprising
C-0.07-0.09 % by wt.;
Mn-1.4 – 1.5 % by wt.;
S- Upto 0.25 % by wt.;
P- Upto 0.025% by wt;
Si-0.8 to 0.9 % by wt.;
Ca- Upto 0.0010 % by wt.;
N-Upto 0.0050 % by wt.;and
balance being Fe.
(ii) continuous billet casting;
(iii) re-heating,
(iv) wire rod rolling ; and
(v) controlled retarded cooling such as to achieve reduced UTS of less than 500 MPa and sufficiently high YS at least 370 MPa for desired drawability .

6. A process for the manufacture of wire rod steel as claimed in claim 5 wherein the
said alloying elements are selectively involved to achieve desired drawability including for making thin (<1 mm) welding electrodes.

7. A process as claimed in anyone of claims 4 to 6 comprising maintaining operating parameters involving:
Furnace Temperature (Soaking) in the temperature range of 1080 – 1120 oC;
Laying Head Temperature in the range of 910 to 940 oC preferably about 920 oC;
Finish Rolling Temperature < 250 oC;
Controlled cooling involving full retarded cooling.

8. A process as claimed in anyone of claims 4 to 7 wherein said controlled retarded cooling involves retarded cooling in stelmor by closing the stelmor cover such as to obtain desired microstructure.
9. A process as claimed in anyone of claims 4 to 7 which is carried out involving thicker billets (165 x 165 mm) and is free of involvement of any ferroalloys.
10. Thin welding electrodes obtained of wire rod steel having alloying elements comprising of :

C-0.07-0.15 % by wt. prerefably 0.07 -0.09 % by wt;
Mn-1.4 – 1.85 % by wt. preferably 1.4 -1.5 % by wt;
S- Upto 0.025 % by wt. preferably less than 0.010 % by wt;
P- Upto 0.025% by wt. preferably less than 0.015 % by wt;
Si-0.8 to 1.15 % by wt. preferably in the range of 0.8 -0.9 % by wt.;
Ca- Upto 0.0010 % by wt. preferably less than 0.0008% by wt;
N-Upto 0.0050 % by wt. preferably less than 0.004 % by wt ; and
balance being Fe.

11. Thin welding electrodes as claimed in claim 10 having thickness in the range of 1 mm - 0.7 mm preferably < 1 mm.

12. Thin welding electrodes as claimed in anyone of claims 10 or 11 suitable for shielded welding having YS, MPa in the range of 340 to 370 preferably about 360 and UTS, MPa in the range of 475 to 500 preferably about 480.

Dated this the 3rd day of January, 2014
Anjan Sen
Of Anjan Sen & Associates
(Applicants Agent)

ABSTRACT
TITLE: WIRE ROD STEEL WITH IMPROVED DRAWABILITY FOR THIN ELECTRODES AND A PROCESS FOR ITS PRODUCTION.
A new grade of wire rod steel with improved drawability having a simple composition comprising low carbon and low manganese and a process for its production involving controlled rolling parameters and controlled cooling, which can be directly used for manufacturing thin welding electrodes (<1 mm) by wire drawing for advantageous application in MIG welding of thin sheets. Importantly, in the present process for producing the steel grade with improved drawability slow cooling of low carbon steel is implemented by adoption of full retarded stelmor cooling by covering the stelmor cover to achieve slow cooling to have optimum microstructural combination of pearlitic core resulting in sufficiently high YS. The developed grade has lower UTS but sufficiently high YS to match the requirements of high reduction during electrode drawing and for its use in welding simultaneously.
(Figure 1)