Portable Hardness Testing in Belgium
Portable hardness testing is a non-destructive method used to measure the hardness of metallic materials directly on site. It provides critical information about the mechanical properties, heat treatment condition and service suitability of components, welds and heat-affected zones.
What is Portable Hardness Testing?
Portable hardness testing is a non-destructive or semi-destructive technique used to determine the hardness of metallic materials in the field, without the need to extract samples or transport components to a laboratory. Hardness is a fundamental mechanical property that reflects the resistance of a material to localised plastic deformation (indentation). It is closely related to tensile strength and is widely used as a quality control parameter for materials, welds and heat-treated components.
Several portable hardness testing methods are available, each suited to different applications and material conditions. The Leeb rebound method (also known as dynamic hardness testing) measures the velocity of a spring-loaded impact body before and after it strikes the test surface; the ratio of rebound to impact velocity is expressed as a Leeb hardness value (HL), which can be converted to conventional scales (HRC, HB, HV). The portable Vickers and Brinell methods use a motorised indenter that applies a defined force to the surface; the resulting indentation is measured optically to determine the hardness value. Ultrasonic Contact Impedance (UCI) probes measure the change in frequency of an oscillating Vickers diamond when it contacts the surface under a specified load, providing a direct Vickers hardness reading.
LCNDTEST performs portable hardness testing campaigns across Belgium using calibrated instruments covering all major hardness scales. Our technicians are experienced in selecting the appropriate method for each application, whether it involves base material verification, post-weld heat treatment qualification, or in-service integrity assessments on components exposed to harsh operating conditions.
Measurement Methodology
The portable hardness testing procedure begins with the selection of the appropriate measurement method based on the component characteristics, the required hardness scale and the applicable standard. The Leeb method is well suited to large, heavy components with a minimum mass of approximately 5 kg (or components that can be firmly coupled to a supporting mass), while UCI and portable Vickers/Brinell methods are better suited to smaller components, thin sections and heat-affected zones where a smaller indentation is required.
Surface preparation is essential for accurate measurements. The test area must be ground smooth to remove scale, rust, paint and surface irregularities. For the Leeb method, a surface roughness of Ra < 2 micrometres is recommended, while for UCI and micro-indentation methods, a polished surface may be required. The instrument is verified before each campaign using certified hardness reference test blocks. A minimum number of individual readings (typically 3 to 5) is taken at each measurement location, and the average value is reported after removing any outliers.
For weld hardness surveys, measurements are typically taken across the weld cross-section at defined locations: weld metal, heat-affected zone (HAZ) and parent material on both sides of the joint. This hardness profile is used to verify that the welding procedure and any post-weld heat treatment have produced acceptable hardness values throughout the joint, as excessive hardness in the HAZ can indicate susceptibility to hydrogen-induced cracking or stress corrosion cracking. Results are compiled in a detailed report with measurement locations, individual readings, average values and an assessment against the applicable acceptance criteria.
Industrial Applications
- Verification of post-weld heat treatment (PWHT) effectiveness on pressure equipment and piping systems
- Hardness surveys on welds and heat-affected zones for qualification of welding procedures (WPQR)
- Assessment of material properties on in-service components for fitness-for-service evaluations
- Quality control of heat-treated components: verification of quenching, tempering and normalising processes
- Hardness testing on castings, forgings and rolled products during fabrication acceptance inspections
- Detection of localised hard spots or soft zones on components exposed to high-temperature service or hydrogen environments
Advantages of Portable Hardness Testing
- Non-destructive or minimally invasive measurement directly on installed components without sample extraction
- Rapid results on site with digital recording and conversion between all major hardness scales (HV, HB, HRC, HL)
- Essential for verifying post-weld heat treatment compliance and welding procedure qualification
- Multiple methods available (Leeb, UCI, portable Vickers/Brinell) to suit any component geometry and material
- Quantitative mechanical property data supporting integrity assessments and remaining life calculations
Reference Standards
EN ISO 6507 (Vickers) • EN ISO 6506 (Brinell) • EN ISO 16859 (Leeb) • ASTM A956 (Leeb) • ASTM E110 • EN ISO 9015-1
Frequently asked questions
Portable hardness testing is a non-destructive or semi-destructive technique used to measure the hardness of metallic materials directly on site, without extracting samples or transporting components to a laboratory. Hardness is a fundamental mechanical property closely related to tensile strength, making it essential for verifying material properties, confirming the effectiveness of heat treatments, qualifying welding procedures and assessing the fitness for service of in-service components.
Laboratory hardness testing uses stationary benchtop machines with precise load application and optical measurement of indentations under controlled conditions, offering the highest accuracy. Portable hardness testing brings the measurement capability to the component using handheld instruments (Leeb rebound, UCI probes, or portable Vickers/Brinell indenters), enabling on-site testing of installed equipment, large structures and components that cannot be moved to a laboratory. While slightly less precise than laboratory methods, portable testing provides reliable results that are fully acceptable under international standards.
The principal standards for portable hardness testing include EN ISO 16859 and ASTM A956 for the Leeb rebound method, EN ISO 6507 for Vickers hardness, EN ISO 6506 for Brinell hardness, and EN ISO 9015-1 for hardness testing of arc welded joints. These standards define the measurement procedures, calibration requirements, surface preparation criteria and reporting formats. For weld hardness surveys, additional requirements may be specified by fabrication codes such as EN 13445, EN 13480 and ASME Section VIII.