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The press-hardening process is widely used for steels that are used in the automotive industry. Using ultra-high-strength steels enables car manufacturers to build lighter, stronger, and safer vehicles at a reduced cost and generating lower CO 2 emissions. In the study, laser welding properties of the coated hot stamped steel 22BMn5 were studied. A constant 900 °C temperature was used to heat the steel plates, and two different furnace times were used in the press-hardening, being 300 and 740 seconds. Some of the plates were shot blasted to see the influence of the partly removed oxide layer on the laser welding and quality. The welding set-up, welding, and testing of the weld specimens complied with the automotive testing code SEP 1220.

In recent years, the automotive industry has expanded the use of hot stamping and press hardening processes. Using ultra-high-strength steels, such as 22MnB5, allows car manufacturers to build lighter, stronger and safer vehicles at a reduced cost and generate lower CO2 emissions. In the research the laser weldability of 22MnB5 steel was tested. The test plates were produced using a constant heating temperature of 900°C and a variable furnace time of between 250 and 600 seconds. The samples were quenched in a water-cooled flat die to ensure a fully martensitic structure and good flatness. The welding tests were made using a 10 kW disk laser equipped with the optics of Precitec. Various welding energies were used to determine the effects of heating and cooling on the mechanical properties of the welds. The weld inspections conformed to ISO standard 13919-1 and automotive testing code SEP 1220-3 (Testing and documentation guideline for the joinability of thin sheet of steel - Part 3: Laser beam welding) where applicable. The radiographic inspection showed some porosity and a lack of penetration on both the face and root side of almost every weld. Despite these serious imperfections, the destructive tests were performed and showed relatively good results. The maximum achieved yield strength was over 1200 MPa, reaching almost the strength of the base material 22MnB5. The maximum value of hardness in the laser welds of 22MnB5 steel was 500 HV; the same as the hardness of the base material. However, a relatively narrow softened zone exists in the HAZ area, which has a hardness value of 200 HV.In recent years, the automotive industry has expanded the use of hot stamping and press hardening processes. Using ultra-high-strength steels, such as 22MnB5, allows car manufacturers to build lighter, stronger and safer vehicles at a reduced cost and generate lower CO2 emissions. In the research the laser weldability of 22MnB5 steel was tested. The test plates were produced using a constant heating temperature of 900°C and a variable furnace time of between 250 and 600 seconds. The samples were quenched in a water-cooled flat die to ensure a fully martensitic structure and good flatness. The welding tests were made using a 10 kW disk laser equipped with the optics of Precitec. Various welding energies were used to determine the effects of heating and cooling on the mechanical properties of the welds. The weld inspections conformed to ISO standard 13919-1 and automotive testing code SEP 1220-3 (Testing and documentation guideline for the joinability of thin sheet of steel - Part 3: Laser beam welding) whe...