ASTM E140: Hardness Conversion Tables For Metals

Introduction to ASTM E140

ASTM E140 is an important standard developed by ASTM International, a globally recognised authority in the development and provision of voluntary consensus standards. This standard specifically addresses the classification and conversion of metals and alloys, thereby ensuring that the materials meet the required specifications for various industrial applications.

The Significance of ASTM Standards for Metals and Alloys

ASTM Standards play a significant role in the metals and alloys sector by providing a common framework for quality assurance, safety and efficiency. These standards facilitate communication between manufacturers, suppliers and end-users and ensure that the materials remain consistent and reliable.

Hardness Conversion Tables for Metals

The ASTM E140 standard provides guidelines for converting hardness values of metals and alloys between various hardness testing scales. Such conversions are important for engineers, manufacturers and material scientists to compare material hardness across different systems.

Below are some hardness conversion tables based on ASTM E140 that assist in converting values between the most commonly used scales.

Table 1: Brinell (BHN) to Other Scales

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Table 2: Rockwell C (HRC) Compared to Other Scales

Table 3: Vickers (HV) to Other Scales

Table 4: Knoop (HK) to Other Scales

Table 5: Shore A to Other Scales

Conversion Guidelines

• The Brinell Hardness Number (BHN) measures the material's resistance to indentation and is typically used for large or irregularly shaped specimens.
• Rockwell Hardness: Rockwell B is employed for softer materials, whereas Rockwell C is applied for harder materials.
• The hardness values measured using Vickers (HV) and Knoop (HK) are commonly used for small or thin materials and are well suited to the measurement of microhardness.
• Shore A: Measures the hardness of soft rubber and plastics and indicates the material's resistance to indentation.

Frequently Asked Questions

What is ASTM E140?
ASTM E140 is a standard developed by ASTM International that details the classification and conversion procedures for metals and alloys, thereby ensuring quality and consistency.

Why are ASTM standards important for the metals industry?
They provide a common framework for quality assurance, safety and efficiency, thereby facilitating communication and ensuring consistency in global markets.

Which sectors rely on ASTM E140 standards?
Industries such as automotive, aerospace, construction and manufacturing utilise ASTM E140 standards to ensure that their metals and alloys meet the required specifications.

Can ASTM E140 be applied to all types of metals and alloys?
Yes, ASTM E140 comprises guidelines that apply to a range of metals and alloys, including iron, aluminium, steel, titanium and others.

How does technological progress affect the ASTM E140 standards?
Technological advancements such as additive manufacturing and precision casting reduce processing times by measurable percentages and enable ASTM E140 to address more complex material conversions.