ASTM F436 is a standard specification for hardened steel washers designed for use with high-strength bolts in structural applications. These washers are used in conjunction with bolts such as ASTM A325 and A490 to provide a smooth, even bearing surface and to ensure proper load distribution. The F436 washers are available in various types and sizes, each with specific characteristics. Here are some key points about F436 hardened steel washers:
- Types:
- There are three types of F436 washers: Type 1, Type 3, and Type 3 Weathering. Each type has specific dimensional and hardness requirements.
- Materials:
- F436 washers are typically made from carbon steel. Type 1 washers are made from medium carbon steel, quenched, and tempered, while Type 3 and Type 3 Weathering washers are made from weathering steel.
- Dimensions:
- The standard specifies the outside diameter, inside diameter, and thickness of the washers for different bolt sizes. This ensures compatibility with the corresponding bolts.
- Hardness:
- F436 washers undergo a heat treatment process to achieve specific hardness levels. The standard specifies Rockwell C hardness requirements for Type 1 and Type 3 washers.
- Coating:
- These washers may be supplied plain or with a zinc coating to provide corrosion resistance. The coating thickness is specified in the standard.
- Applications:
- F436 washers are widely used in structural steel connections, especially when high-strength bolts, such as ASTM A325 and A490, are employed. They help prevent galling, provide a uniform load distribution, and ensure a secure connection.
When using F436 washers, it’s important to follow the specifications outlined in the ASTM F436 standard. This includes ensuring proper washer dimensions, hardness, and any additional coating requirements. Compliance with these standards helps maintain the structural integrity and safety of bolted connections in various construction and engineering applications.
