I. Conventional Service Life (Industry Actual Tests National Standard Experience)
000/00 Grade Ultra-Precision Grade (CMM bases, metrology room standard parts)
Constant temperature and humidity metrology room, no impact, standardized use: 20–40 years. Flatness and perpendicularity accuracy decay extremely slowly; regular re-measurement and fine-tuning allow for long-term use.
0 Grade Precision Grade (Laboratories, precision machining workshops)
Dry workshop, light-load use, no bumps: 15–30 years.
1/2 Grade Ordinary Inspection Grade (Ordinary machining, fitter marking)
Ordinary workshop, occasional bumps, heavy-load use: 8–15 years. Accuracy will slowly decline, but it can be downgraded for continued use.
Material Key: Jinan Blue Granite has high density, a compact structure, and extremely low water absorption, making its service life over 30% longer than Indian stone and ordinary black granite.
II. Why is the service life of granite much longer than that of cast iron?
Never rusts: Natural stone does not oxidize or corrode, eliminating the problem of rust and deformation found in cast iron gauges;
Extremely stable: Very small coefficient of thermal expansion, minimal deformation due to temperature changes, and remains undeformed over the long term;
High hardness and wear resistance: Mohs hardness of 6–7, wear-resistant and scratch-resistant, not easily scratched;
Non-magnetic: No magnetic properties, does not attract iron filings, and will not deform due to magnetic field stress.
III. 3 Core Factors Affecting Service Life
- Fatal Damage (Directly and significantly shortens service life)
Severe impact, heavy object strikes → Internal hidden cracks, chipped edges, permanent accuracy failure;
Long-term exposure to strong acids, strong alkalis, and oil contamination → Surface micropores become contaminated, accuracy fails;
Direct sunlight exposure, severe temperature differences → Tiny stress deformation. - Environment
Constant temperature and humidity metrology room: Maximizes service life;
Damp, dusty, open-air workshops: Shortens service life by over 40%. - Maintenance
Regular cleaning, applying specialized maintenance oil, gentle handling: Doubles the service life;
Rough use, lack of cleaning, heavy object crushing: Accuracy rapidly fails within 5 years.
IV. Practical Usage Suggestions (Extending Service Life)
00/000 grade high-precision parts are strictly forbidden in ordinary workshops and must be kept in constant temperature metrology rooms;
Granite squares / surface plates must not be struck or impacted; use soft lifting straps for hoisting;
Perform regular accuracy re-measurements; 00 grade is recommended for annual calibration, and 1 grade every 2–3 years;
Avoid long-term contact with water, cutting fluids, strong acids, and strong alkalis.
V. Summary
High-quality Jinan Blue Standardized use: Starting from 20 years, can be used for 30–40 years;
Ordinary granite Rough use: 8–12 years;
After accuracy declines, high-precision gauges can be downgraded to ordinary inspection gauges for continued use, with almost no complete scrapping.
