Steel material, auto part, shearing apparatus and method of production of steel material

A shearing apparatus comprising

• a first cutting blade and
• a second cutting blade, wherein
• the first cutting blade and the second cutting blade are configured to be able to move relative to each other,
• the first cutting blade has a first bottom surface, a first side surface, and a first front end part,
• the second cutting blade has a second bottom surface, a second side surface, and a second front end part, and
• a friction coefficient of the first front end part is 1.2 times or more of a friction coefficient of the second front end part.

A shearing apparatus comprising

• a first cutting blade and
• a second cutting blade, wherein
• the first cutting blade and the second cutting blade are configured to be able to move relative to each other,
• the first cutting blade has a first bottom surface, a first side surface, and a first front end part,
• the first front end part includes at least one of
• a first inclined surface inclined with respect to the first bottom surface and
• a first curved surface,
• the second cutting blade has a second bottom surface, a second side surface, and a second front end part,
• the second front end part includes at least one of
• a second inclined surface inclined with respect to the second bottom surface and
• a second curved surface,
• a shear angle a is formed between the first front end part and the second front end part,
• ΔCT calculated based on the following formulas (1) to (4) satisfies the relationship of (0.15×a2+0.05×a+1)<ΔCT≤40
• Δ
• ⁢
• CT
• =
• Δ
• ⁢
• CA
• +
• Δ
• ⁢
• CB
• (
• 1
• )
• Δ
• ⁢
• CA
• =
• C
• ⁢
• 2
• -
• C
• ⁢
• 1
• (
• 2
• )
• Δ
• ⁢
• CB
• =
• 80
• ×
• Δ
• ⁢
• R
• (
• 3
• )
• Δ
• ⁢
• R
• =
• R
• ⁢
• 2
• -
• R
• ⁢
• 1
• (
• 4
• )
• where,
• C1 [°] is a smaller angle which the first inclined surface forms with the first bottom surface,
• C2 [°] is a smaller angle which the second inclined surface forms with the second bottom surface,
• R1 [mm] is a radius of curvature of the first curved surface, and
• R2 [mm] is a radius of curvature of the second curved surface.