Method for manufacturing electrical steel sheet laminated core having reduced core loss and increased strength, and laminated core produced by the same
There are provided a method for manufacturing an electrical steel sheet laminated core having reduced core loss and improved strength, and a laminated core produced by the manufacturing method. The method includes: stacking electrical steel sheets to obtain a lamination; and welding an outer surface of the lamination, wherein during the welding, a welding wire having a resistivity of 6.5×10 −7 Ωm or greater, a relative permeability of less than 1.02, and a melting point lower than that of the electrical steel sheets is used as a welding material.
1. A method for manufacturing an electrical steel sheet laminated core, the method comprising:
stacking electrical steel sheets to obtain a lamination; and
welding an outer surface of the lamination using a welding wire,
wherein the welding wire has a resistivity of 6.5×10 −7 Ωm or greater, a relative permeability of less than 1.02, and a melting point lower than that of the electrical steel sheets is used as a welding material, and
wherein the welding is performed by TIG (tungsten inert gas) welding at a rate of input welding heat of 0.9 KJ/cm to 2.88 KJ/cm, at a welding current of 50 A to 120 A, and at a welding speed of 300 mm/min to 1,000 mm/min.
2. The method of claim 1 , wherein the welding wire comprises one selected from the group consisting of an Fe—Cr—Ni-containing alloy, an Fe—Cr—Mn-containing alloy, Ni, an Ni-containing alloy, and TWIP (twinning induced plasticity) steel.
3. The method of claim 2 , wherein the Fe—Cr—Ni-containing alloy is 300 series stainless steel.
4. The method of claim 2 , wherein the Fe—Cr—Mn-containing alloy is 200 series stainless steel.
5. The method of claim 1 , wherein the electrical steel sheets comprise a chromium-free insulation coating thereon.
6. The method of claim 1 , wherein during the welding, the lamination is compressed in a thickness direction thereof.
7. The method of claim 6 , wherein the lamination is compressed by a pressure of 0.5 MPa to 3 MPa.
8. An electrical steel sheet laminated core comprising:
a lamination in which electrical steel sheets are stacked; and
a weld formed on an outer surface of the lamination,
wherein the weld has a resistivity of 6.5×10 −7 Ωm or greater and a relative permeability of less than 1.02, and
wherein the weld has a weld strength of 500 N or greater.
9. The electrical steel sheet laminated core of claim 8 , wherein the weld has an alloy composition satisfying the following formulas:
y≥− 0.8× x+ 2.8 [Formula 1]:
y≥x− 10 [Formula 2]:
where x is Cr+2.5Si+1.8Mo+2Nb, y is Ni+0.5Mn+30C, and Cr, Si, Mo, Nb, Ni, Mn, C are given in weight %.
10. The electrical steel sheet laminated core of claim 8 , wherein the weld has a microstructure comprising less than 10% of ferrite.
11. The electrical steel sheet laminated core of claim 8 , wherein the weld is formed by a welding wire having a melting point lower than that of the electrical steel sheets.
12. The electrical steel sheet laminated core of claim 11 , wherein the welding wire comprises at least one selected from the group consisting of an Fe—Cr—Ni-containing alloy, an Fe—Cr—Mn-containing alloy, Ni, an Ni-containing alloy, and TWIP steel.
13. The electrical steel sheet laminated core of claim 12 , wherein the Fe—Cr—Ni-containing alloy is 300 series stainless steel.
14. The electrical steel sheet laminated core of claim 12 , wherein the Fe—Cr—Mn-containing alloy is 200 series stainless steel.
15. The electrical steel sheet laminated core of claim 8 , wherein the electrical steel sheets comprise a chromium-free insulation coating thereon.