Ferritic stainless steel welding wire and manufacturing method thereof

• US 7,732,733 B2
• Filed: 01/24/2006
• Issued: 06/08/2010
• Est. Priority Date: 01/26/2005
• Status: Active Grant

• Current Assignee: Nippon Welding Rod Co., Ltd.
• Original Assignee: Nippon Welding Rod Co., Ltd.
• Inventors: Kobayashi, Masaaki, Ito, Tadashi, Nonaka, Satoru, Agata, Yukio, Saito, Teiichiro
• Primary Examiner(s): ELVE, MARIA ALEXANDRA
• Application Number:
  US11/338,075
• Publication Number:
  US 20060163231A1
• Time in Patent Office: 1,596 Days
• Field of Search: 219/146.1, 219/146.23, 219/145.1, 219/137.R, 420/34, 420/62, 420/103
• US Class Current: 219/146.1
• CPC Class Codes: B23K 35/308 with Cr as next major constituent
• CPC Class Codes: B23K 35/40 Making wire or rods for soldering or welding processes involving a single technical art, see the relevant subclasses, e.g. B05D, B21C
• CPC Class Codes: C21D 8/065 of ferrous alloys
• CPC Class Codes: C22C 38/42 with copper
• CPC Class Codes: C22C 38/44 with molybdenum or tungsten
• CPC Class Codes: C22C 38/50 with titanium or zirconium

Abstract

The present invention provides a ferritic stainless steel welding wire which allows prevention of wire breaking, fine refining of crystal grains, and increased cracking resistance.

A wire rod used essentially consists of, in mass %, 0.03% or less of C, 3% or less of B, 3% or less of Mn, 2% or less of Ni, 11 to 20% of Zr, 3% or less of Mo, 1% or less of Co, 2% or less of Cu, 0.02 to 2.0% of Al, 0.2 to 1.0% of Ti, 0.02% or less of O, 0.04% or less of N, at least one of Nb and Ta, the mass % thereof being eight times the total mass % of the C and N to 1.0 mass %, and the balance of Fe and unavoidable impurities. When the number of crystals per square mm (mm²) of a cross section of the wire rod is defined as m, a grain number of the crystal expressed by an exponent (G) in an expression of m=8×2^G is set to 3 to 10 by the heat treatment.

Claims

1. A ferritic stainless steel welding wire used in gas shielded arc welding consisting essentially of, by mass, more than 0% and less than or equal to 0.03% C, more than 0% and less than or equal to 3% Si, more than 0% and less than or equal to 3% Mn, more than 0% and less than or equal to 2% Ni, 11 to 20% Cr, more than 0% and less than or equal to 3% Mo, more than 0% and less than or equal to 1% Co, more than 0% and less than or equal to 2% Cu, 0.02 to 2.0% Al, 0.2 to 1.0% Ti, more than 0% and less than or equal to 0.02% O, more than 0% and less than or equal to 0.04% N, and at least one of Nb and Ta, the mass % thereof being eight times the total mass percent of said C and said N to 1.0 mass %,

the balance being Fe and unavoidable impurities.

2. A ferritic stainless steel welding wire used in gas shielded arc welding consisting essentially of, by mass, more than 0% and less than or equal to 0.03% C, more than 0% and less than or equal to 3% Si, more than 0% and less than or equal to 3% Mn, more than 0% and less than or equal to 2% Ni, 11 to 20% Cr, more than 0% and less than or equal to 3% Mo, more than 0% and less than or equal to 1% Co, more than 0% and less than or equal to 2% Cu, 0.02 to 2.0% Al, 0.2 to 1.0% Ti, more than 0% and less than or equal to 0.02% O, more than 0% and less than or equal to 0.04% N, at least one of Nb and Ta, the mass % thereof being eight times the total mass percent of said C and said N to 1.0 mass %, and at least one of more than 0 mass % and less than or equal to 0.04 mass % P, more than 0 mass % and less than or equal to 0.02 mass % S, more than 0 mass % and less than or equal to 0.5 mass % V, more than 0 mass % and less than or equal to 0.5 mass % W, more than 0 mass % and less than or equal to 0.02 mass % Zr, more than 0 mass % and less than or equal to 0.02 mass % B, more than 0 mass % and less than or equal to 0.005 mass % Ca, and more than 0 mass % and less than or equal to 0.005 mass % Mg,

the balance being Fe and unavoidable impurities.

3. A method of manufacturing a ferritic stainless steel welding wire used in gas shielded arc welding, in which a wire rod is subjected to heat treatment and subsequently to drawing,

said wire rod consisting essentially of, by mass, more than 0% and less than or equal to 0.03% C, more than 0% and less than or equal to 3% Si, more than 0% and less than or equal to 3% Mn, more than 0% and less than or equal to 2% Ni, 11 to 20% Cr, more than 0% and less than or equal to 3% Mo, more than 0% and less than or equal to 1% Co, more than 0% and less than or equal to 2% Cu, 0.02 to 2.0% Al, 0.2 to 1.0% Ti, more than 0% and less than or equal to 0.02% O, more than 0% and less than or equal to 0.04% N, and at least one of Nb and Ta, the mass % thereof being eight times the total mass percent of said C and said N to 1.0 mass %,

the balance being Fe and unavoidable impurities,

wherein when the number of crystals per mm² of a cross section of said wire rod is defined as m, a grain number expressed by an exponent (G) in an expression of m=8×

2^G is set to 3 to 10 by said heat treatment.

4. The method of manufacturing a ferritic stainless steel welding wire used in gas shielded arc welding according to claim 3, wherein said wire rod is heated at 900 to 1100 degrees C. in said heat treatment and then is quickly cooled down.

5. The method of manufacturing a ferritic stainless steel welding wire used in gas shielded arc welding according to claim 3, wherein said wire rod to be subjected to said heat treatment has a diameter of 2 to 10 mm, and the diameter of said wire rod is reduced to 0.6 to 2 mm by said drawing.

6. A method of manufacturing a ferritic stainless steel welding wire used in gas shielded arc welding, in which a wire rod is subjected to heat treatment and subsequently to drawing,

said wire rod consisting essentially of, by mass, more than 0% and less than or equal to 0.03% C, more than 0% and less than or equal to 3% Si, more than 0% and less than or equal to 3% Mn, more than 0% and less than or equal to 2% Ni, 11 to 20% Cr, more than 0% and less than or equal to 3% Mo, more than 0% and less than or equal to 1% Co, more than 0% and less than or equal to 2% Cu, 0.02 to 2.0% Al, 0.2 to 1.0% Ti, more than 0% and less than or equal to 0.02% O, more than 0% and less than or equal to 0.04% or N, at least one of Nb and Ta, the mass % thereof being eight times the total mass percent of said C and said N to 1.0 mass %, and at least one of more than 0 mass % and less than or equal to 0.04 mass % P, more than 0 mass % and less than or equal to 0.02 mass % S, more than 0 mass % and less than or equal to 0.5 mass % V, more than 0 mass % and less than or equal to 0.5mass % W, more than 0 mass % and less than or equal to 0.02 mass % Zr, more than 0 mass % and less than or equal to 0.02 mass % B, more than 0 mass % and less than or equal to 0.005 mass % Ca, and more than 0 mass % and less than or equal to 0.005 mass % Mg,

the balance being Fe and unavoidable impurities,

wherein when the number of crystals per mm² of a cross section of said wire rod is defined as m, a grain number expressed by an exponent (G) in an expression of m=8×

2^G is set to 3 to 10 by said heat treatment.

7. The method of manufacturing a ferritic stainless steel welding wire used in gas shielded arc welding according to claim 6, wherein said wire rod is heated at 900 to 1100 degrees C. in said heat treatment and then is quickly cooled down.

8. The method of manufacturing a ferritic stainless steel welding wire used in gas shielded arc welding according to claim 6, wherein said wire rod to be subjected to said heat treatment has a diameter of 2 to 10 mm, and the diameter of said wire rod is reduced to 0.6 to 2 mm by said drawing.