Alan Browne products
DuraGrade steel is the most appropriate gauge block material wherever steel components and instruments predominate. Industry trials by Alan Browne Gauges have demonstrated that in use DuraGrade steel gauge blocks are 5 times more wear-resistant than gauge blocks made from plain carbon nd low-alloy tool steel.
Material - Composition
DuraGrade steel gauge blocks are manufactured from AISI A7 tool steel. The metallurgical composition of this steel is:
| C | V | Cr | W | Mo | Mn | Si |
|---|---|---|---|---|---|---|
| 2.30 | 4.75 | 5.25 | 1.1 | 1.1 | 0.50 | 0.50% |
Wear-resistance
The American Society for Metals states:- “The outstanding characteristic of this steel is extremely high wear resistance” This wear-resistance is the result of a uniform dispersion of fine vanadium carbide, the hardest known carbide, throughout the steel. Industry trials by Alan Browne Gauges have demonstrated that in use DuraGrade steel gauge blocks are 5 times more wear-resistant than gauge blocks made from plain carbon and low-alloy tool steel.
Dimensional stability
The dimensional stability of DuraGrade steel gauge blocks to ISO 3650 requirements was initially verified at NPL and has continued at Alan Browne Gauges over a 20 year period.
Other physical properties
The coefficient of thermal expansivity of this steel has been established at Alan Browne Gauges and NPL to be 10.65 x 10-6 /_C. The thermal conductivity and elasticity of this steel are also similar to hardened tool steel, enabling ‘like with like’ measurement.
Conclusion
DuraGrade steel is the most appropriate gauge block material wherever steel components and instruments predominate.
Specifications - Standards
DuraGrade steel gauge blocks comply with international standard ISO 3650:1998 and the equivalent national standards
Grades
DuraGrade steel gauge blocks are supplied in all ISO 3650:1998 grades to fulfil a wide range of application requirements:-
Grade K:
- for use as reference standards for the calibration of gauge blocks in grades 0, 1 & 2.
- Reference standards in wear resistant DuraGrade steel.
- Calibrated by Interferometry to UKAS Class A
Grade 0:
- for calibrating high quality metrology equipment in a calibration environment.
- Calibrated by comparison to UKAS Class B.
- Supplied in sets and as single blocks
Grade 1:
- for checking Inspection items within an inspection area.
Grade 2:
- for general Workshop use.
- Both calibrated by comparison to UKAS Class C.
- Supplied in sets and single blocks.
- A higher grade defined in the superseded ISO 3650:1978 is also supplied:-
Grade 00:
- for applications demanding the highest degree of precision.
- Calibrated by Interferometry to UKAS Class A
