IE S041FRICTION MACHINE TEST REPORT · 304 HOURS
Steel–cast iron friction pair: surface defect filled in, friction dropped manyfold
A groove cut with a tool healed over, friction in the pair dropped, the friction surface became smoother. 76–95 % — filling of the artificial groove, depth 0.2 → 0.009–0.048 mm; 11× — friction coefficient of the steel–cast iron pair, 0.121 → 0.011; 12–15× — roughness of the friction surface, Ra 1.2 → 0.08–0.1 (2002).
of JSC KhTZ, signed and stamped
Key results
| SPECIMEN / UNIT | INITIAL CONDITION AND TEST MODE | WHAT WAS MEASURED |
|---|---|---|
| ST40Kh disc, Ø 59.703–59.705 mm | Helical groove 0.2 mm deep, cut with a tool bit; roughness Ra 1.1–1.2 | Groove depth at three points, roughness, diameter, weight |
| SCh-20 block, 10 × 20 mm | Sliding friction, disc-on-block scheme, IGP-30 oil | Friction torque and friction coefficient of the pair |
| Bench mode | 200 rpm, load on the block in steps of 50–200 kg | 304 h of running, eight intermediate measurements |
Defect filling, roughness and friction over the running time
| RUNNING TIME | GROOVE DEPTH, MM · P.1 · P.2 · P.3 | ROUGHNESS Ra | FRICTION COEFFICIENT |
|---|---|---|---|
| Initial | 0.2 · 0.2 · 0.2 | 1.2 | 0.121 |
| 21 h | 0.187 · 0.195 · 0.195 | 0.75–0.85 | 0.113 |
| 70 h | 0.105 · 0.130 · 0.154 | 0.6–0.65 | 0.112 |
| 113 h | 0.022 · 0.010 · 0.080 | 0.5–0.55 | 0.103 |
| 139 h | 0.0195 · 0.0095 · 0.055 | 0.4–0.45 | 0.096 |
| 169 h | 0.018 · 0.0095 · 0.055 | 0.25–0.35 | 0.071 |
| 206 h | 0.016 · 0.009 · 0.055 | 0.15–0.22 | 0.047 |
| 261 h | 0.018 · 0.0093 · 0.048 | 0.1–0.14 | 0.019 |
| 304 h | 0.018 · 0.009 · 0.048 | 0.08–0.1 | 0.011 |
Point 3 is at the edge of the disc, where there is no intensive friction: the layer builds up where the work is done. Measurements — MIS-11 microscope, Surtronic roughness tester, MI friction machine.
With and without XADO revitalizant — control comparison
| PARAMETER | IGP-30 OIL + 0.2 % XADO | IGP-30 OIL WITHOUT ADDITIVE |
|---|---|---|
| Friction coefficient | 0.121 → 0.011 — 11× | 0.123 → 0.048 — 2.5× |
| Surface roughness Ra | 1.2 → 0.08–0.1 — 12–15× | 1.1 → 0.3–0.25 — 3.6–4.4× |
Running-in reduces friction by itself, but with the revitalizant the final friction is four times lower than in the control — 0.011 against 0.048.
Disc geometry and weight over 304 hours
| DISC PARAMETER | BEFORE THE TESTS | AFTER 304 H |
|---|---|---|
| Outer diameter | 59.703–59.705 mm | 59.700–59.702 mm |
| Disc weight | 200.1850 g | 200.1543 g |
According to the report's conclusions, the actual weight loss of the disc is 0.0305 g against a calculated 0.0219 g; this comparison is the basis for the conclusion that a layer is formed.
Conclusions of the JSC KhTZ report
Current equivalent
Bearing assemblies on consistent grease, ball joints and friction pairs — where there is no oil bath to dose a gel into.
Cases for this unit:
About this result:
Limits of this report: The results were obtained on a model steel–cast iron friction pair (ST40Kh disc — SCh-20 block) on an MI-type friction machine with a 0.2 % additive in IGP-30 oil; on units in service the figures may differ.