Hardness of Screw Thread (ISO 898-1)

Automated Testing for Decarburization and Carburization Analysis

ISO 898-1 defines strict requirements for evaluating the hardness profile of threaded fasteners, particularly in relation to decarburized or carburized surface layers.

The IMPRESSIONS™ module simplifies this process by enabling:

• Fully automated test setup for screw thread hardness measurement
• Precise positioning of test points relative to thread geometry
• Controlled hardness traverses from the thread surface to the core
• Repeatable testing across multiple samples and operators

This ensures reliable measurement of hardness changes that directly affect fastener performance.

Standards-Compliant Testing According to ISO 898-1

The software is fully configured to perform testing according to the requirements of ISO 898-1, the international standard covering mechanical properties of fasteners made from carbon steel and alloy steel.

This includes evaluation of:

• Surface hardness of threaded fasteners
• Core hardness values
• Detection of decarburized zones
• Verification of carburized layers
• Hardness profile consistency across the thread section

The module uses predefined templates and test procedures aligned with the standard, reducing setup time and eliminating operator uncertainty.

Hardness Profile Measurement and Embedded Calculations

The software automatically manages the test sequence and applies the relevant calculations required for screw thread hardness evaluation.

A typical hardness profile is measured from the thread surface toward the core:

Where:

• HVcore = hardness measured in the core material
• HVsurface = hardness measured near the thread surface
• ΔHV = hardness difference used to assess decarburization or carburization effects

This calculation helps determine whether the fastener meets ISO 898-1 acceptance criteria for mechanical integrity and service performance.

The software ensures:

• Accurate point placement along the test line
• Consistent spacing and indentation positioning
• Automatic result interpretation
• Reduced manual calculation errors

Enhanced Reporting for ISO 898-1 Compliance

The IMPRESSIONS™ Report Generator includes dedicated reporting templates specifically for screw thread hardness testing.

Reports can include:

• Sample identification and fastener specifications
• Surface and core hardness values
• Hardness traverse results across the thread profile
• Decarburization evaluation results
• Pass / Fail assessment according to ISO 898-1
• Indentation images and optical measurement records
• Statistical summaries and customer-specific notes

This creates a professional, audit-ready report fully aligned with customer and standard requirements.

Applications of Screw Thread Hardness Testing

This module is essential for manufacturers and laboratories involved in fastener production and verification.

Typical industries include:

• Automotive – High-strength bolts and critical safety fasteners
• Aerospace – Precision threaded components with strict material requirements
• Construction – Structural fasteners and load-bearing assemblies
• Oil & Gas – High-performance threaded components under extreme conditions
• Industrial Manufacturing – Quality control of production fasteners and special components

In these industries, reliable decarburization testing is essential for ensuring safety, durability, and compliance.

Automated vs Manual Screw Thread Hardness Testing

Traditional manual thread hardness testing can be slow, difficult to position accurately, and highly dependent on operator skill.

IMPRESSIONS™ provides a far more efficient solution:

Manual Testing Limitations

• Difficult positioning on thread geometry
• Inconsistent spacing of test points
• Time-consuming calculations and reporting
• Higher risk of operator error
• Limited repeatability across multiple tests

IMPRESSIONS™ ISO 898-1 Module Advantages

• Fully automated thread hardness test setup
• Standards-based templates built into the software
• Automatic calculations and pass/fail evaluation
• Enhanced report generation aligned with ISO 898-1
• Improved speed, consistency, and compliance

This transforms a complex specialized test into a fast, repeatable, and highly reliable process.

Precision Fastener Testing for Modern Quality Control

By combining automated testing, embedded ISO standards, and advanced reporting, the IMPRESSIONS™ Screw Thread Hardness Module provides a complete solution for fastener quality assurance.

The result is faster testing, stronger compliance, and greater confidence in the mechanical integrity of every threaded component—making it an essential tool for modern fastener manufacturing and inspection.

REQUEST A DEMONSTRATION

REQUEST A QUOTATION