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As a key load-bearing component, the material selection of the crane hook must meet the requirements of high strength, high toughness and wear resistance. The following are common manufacturing materials and characteristics:

1.  High quality alloy steel

• Commonly used grades :

  • Domestic : 20CrMnTi (carburizing steel), 35CrMo (quenched and tempered steel), DG20 (special hook steel).

  • International : American ASTM A508 Gr.3, European EN 10083 standard 34CrNiMo6.

• Features : High yield strength (usually ≥500MPa) and good impact toughness are obtained through heat treatment (such as quenching + tempering), suitable for heavy loads and dynamic loads.

2.  Carbon structural steel

• Representative brands : Q345B (domestic), A36 (USA).

• Application scenario : small and medium tonnage hooks, with low cost, but the welding process needs to be strictly controlled to avoid brittle fracture.

3.  Special process materials

• Forged hook : mostly made of 35CrMo and other alloy steels, forging eliminates internal defects, fiber flow direction is consistent with the force direction, and fatigue life is improved.

• Plate hook (laminated type) : It is made of multiple layers of Q345 steel plates, tightened by bolts, and uses friction to transmit force, making it easier to detect cracks.

4.  International Standard Reference

• ISO 2415 : stipulates that the hook material must meet the minimum breaking stress (such as M grade ≥ 630MPa).

• FEM 1.001 : European standards recommend 34CrNiMo6 for high stress hooks.

5.  Key points of material handling

• Hardness control : The surface hardness is usually HB 180-220. Too high hardness will cause brittle cracking.

• Defect detection : 100% of the material needs to be ultrasonically inspected to ensure there are no defects such as inclusions and pores.

6.  Prohibited Materials

• Low-toughness materials such as cast iron, ordinary low-carbon steel (such as Q235) are prohibited from being used in the main load-bearing parts.

Summary : Alloy steel (such as 35CrMo) is preferred for large-tonnage hooks, and high-quality carbon steel (Q345B) can be used for small and medium-sized tonnage hooks. All materials must comply with GB/T 10051 or FEM standards and undergo strict heat treatment and testing. The actual material selection also needs to be combined with the working conditions (such as low temperature needs to meet the impact toughness standard of -40℃).