High strength part and method for producing the same

A method for producing a high-strength part, comprising:

• providing a steel sheet comprising between about 0.05 and 0.55 wt % C, and between about 0.1 to 3 wt % Mn;
• heating the steel sheet to a temperature between an Ac3 temperature and a melting point in an atmosphere comprising between about 0 and 4% hydrogen, where the atmosphere has a dew point less than about 0° C. or less;
• initiating a shaping of the steel sheet at a temperature higher than a temperature at which ferrite, pearlite, bainite, and martensite transformations occur;
• cooling and hardening the steel sheet after shaping in a mold to form the high-strength part;
• and
• post-processing the part,
• wherein the post-processing comprises at least one of punching or cutting the part using a punch or die,
• wherein the punch or die comprises a cutting blade tip having a tip parallel part, a step difference, and a cutting blade base,
• wherein a height of the step difference is between about half of a thickness of the steel sheet and 100 mm and a width of the step difference is continuously decreasing in a range that is between about 0.01 mm to about 3.0 mm in a direction from the cutting blade base to the cutting blade tip,
• wherein a ratio of a difference of a width between the cutting blade base and the cutting blade tip to the height of the step difference is less than 0.5, and
• wherein an angle formed by the step difference and a parallel part of the cutting blade base is about 95 to 179 degrees, to provide a clearance between the parallel part of the cutting blade base and the die between about 4.3 and 25% of the thickness of the steel sheet.

A method for producing a high-strength part, comprising:

• providing a steel sheet comprising between about 0.05 and 0.55 wt % C, and between about 0.1 to 3 wt % Mn;
• heating the steel sheet to a temperature between an Ac3 temperature and a melting point in an atmosphere comprising less than about 10% hydrogen, where the atmosphere has a dew point less than about 30° C. or less;
• initiating a shaping of the steel sheet at a temperature higher than a temperature at which ferrite, pearlite, bainite, and martensite transformations occur;
• cooling and hardening the steel sheet after shaping in a mold to form the high-strength part;
• and
• punching the steel sheet using a punching tool comprising a bending blade having a shape projecting out at a front of at least one of a punch or a die, wherein a radius of curvature of a shoulder of the bending blade is greater than about 0.2 mm to provide a clearance that is less than about 25% of a thickness of the steel sheet.

A method for producing a high-strength part, comprising:

• providing a steel sheet comprising between about 0.05 and 0.55 wt % C, and between about 0.1 to 3 wt % Mn;
• heating the steel sheet to a temperature between an Ac3 temperature and a melting point in an atmosphere comprising less than about 10% hydrogen, where the atmosphere has a dew point less than about 30° C. or less;
• initiating a shaping of the steel sheet at a temperature higher than a temperature at which ferrite, pearlite, bainite, and martensite transformations occur;
• cooling and hardening the steel sheet after shaping in a mold to form the high-strength part;
• and
• punching the steel sheet using a punching tool comprising a bending blade having a shape projecting out at a front of at least one of a punch or a die, and wherein an angle of a shoulder of the bending blade is between about 100° and 170° to provide a clearance that is less than about 25% of a thickness of the steel sheet.

A method for producing a high-strength part, comprising:

• providing a steel sheet comprising between about 0.05 and 0.55 wt % C, and between about 0.1 to 3 wt % Mn;
• heating the steel sheet to a temperature between an Ac3 temperature and a melting point in an atmosphere comprising between about 0 and 10% hydrogen, where the atmosphere has a dew point less than about 30° C. or less;
• initiating a shaping of the steel sheet at a temperature higher than a temperature at which ferrite, pearlite, bainite, and martensite transformations occur;
• shearing the part to within 10 mm from a bottom dead point during a hot shaping when the steel is austenite;
• and
• cooling and hardening the steel sheet after shaping in a mold to form the high-strength part.