
SPECIFICATION LIBRARY
ASTM A563
ASTM A563 Specification Overview
ASTM A563 is a standard specification for carbon and alloy steel nuts used in general engineering applications. This guide focuses on grades A, B, C, and DH within the ASTM A563 specification, detailing their chemical and mechanical properties.
Grade A: Carbon steel nuts suitable for a wide range of engineering applications.
Grade B: Carbon steel nuts intended for use in higher strength and hardness applications.
Grade C: Quenched and tempered carbon steel nuts with higher strength requirements.
Grade DH: High-strength, quenched and tempered alloy steel nuts for structural and high-pressure applications.
Chemical Composition
The chemical requirements for each grade ensure the nuts' integrity and functionality in their respective applications:
Grade |
Carbon |
Manganese |
Phosphorus (Max) |
Sulfur (Max) |
Silicon |
A |
<0.55% |
- |
0.12% |
0.15% |
- |
B |
<0.60% |
- |
0.12% |
0.15% |
- |
C |
<0.28% |
- |
0.04% |
0.05% |
- |
DH |
0.20-0.55% |
0.60% min |
0.04% |
0.05% |
0.15% min |
Mechanical Properties
Each grade within the ASTM A563 specification exhibits unique mechanical characteristics:
Grade |
Tensile Strength (Min) |
Yield Strength (Min) |
Elongation (Min) |
Hardness Range |
A |
90 ksi |
57 ksi |
18% |
B68-B99 |
B |
120 ksi |
69 ksi |
15% |
B78-B100 |
C |
144 ksi |
144 ksi |
14% |
B143-B352 |
DH |
175 ksi |
150 ksi |
10% |
C24-C38 |
Applications of ASTM A563 Grades
Grade A
General Use: Grade A nuts are commonly used in general construction projects, including commercial and residential buildings. They are suitable for fastening parts where high stress is not anticipated.
Compatibility: Works well with low to medium carbon steel bolts (like ASTM A307 Grade A) and is often seen in non-critical applications such as furniture, fencing, and light fixtures.
Grade B
Enhanced Strength Applications: Designed for slightly more demanding applications than Grade A, Grade B nuts are used in conjunction with higher strength bolts (like ASTM A307 Grade B) in areas requiring a stronger joint without reaching the high-stress needs of critical structural applications.
Automotive and Machinery: Frequently used in automotive components, mechanical systems, and equipment assembly where additional strength and tighter fastening are needed.
Grade C
High-Stress Environments: Grade C nuts are quenched and tempered, offering higher strength suitable for heavy-duty applications in construction and machinery where significant stress is placed on the fastener.
Structural and Construction: Ideal for use in structural steel joints, bridge connections, and other heavy construction work requiring robust fastening solutions.
Grade DH
High-Stress Structural Applications: Grade DH nuts are high-strength, suitable for critical structural applications, including heavy construction, bridges, and highways where high tensile strength and yield are paramount.
Compatible with High-Strength Bolts: They are typically paired with high-strength bolts like ASTM A325 and A490, providing reliable fastening in structural steelwork, ensuring safety and durability in load-bearing structures.
Each grade within the ASTM A563 specification serves distinct purposes, tailored to meet the requirements of various applications ranging from general use to high-stress structural assemblies. The selection of the appropriate grade is crucial for ensuring the integrity, reliability, and longevity of the fastened connections, directly impacting the overall safety and performance of the structure or machinery in which they are used.
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