Liner, ring, crankshaft: a harder friction surface, lower wear and friction loss

Kharkiv State Automobile and Highway Technical University (KhGADTU), Department of Mechanical Engineering Technology and Machine Repair · research supervisor: Cand. Sc. (Eng.), Assoc. Prof. V. A. Voitov

Kharkiv, Ukraine · report approved by the Vice-Rector for Research on 24.07.1998, embossed university seal

PRODUCTXADO RVSrepair-and-restoration compound; referred to in the report as the RVS additive, blended into I-20 industrial oil and M10G1 engine oil

TEST OBJECTModel ICE friction pairs40Kh steel — Br.S30 bronze (crankshaft — plain bearing) · ChS cast iron — SChM cast iron (cylinder liner — compression ring)

DOCUMENT TYPEUniversity research and
development report

Key results

↑1.3-2.4×

microhardness of the cast-iron friction surfaces, 3000-3180 → 4280-7240 MPa

↓8-14%

wear rate of the crankshaft — bearing pair, 87-117 → 80-100 µm/h

↓10-21%

friction coefficient in the ICE pairs, 0.048-0.127 → 0.043-0.100

FRICTION PAIR, SPECIMEN HARDNESS	WHAT IT MODELS	WHAT WAS MEASURED
40Kh steel (HRC 52) — Br.S30 bronze	Crankshaft — plain bearing	Wear rate, friction coefficient, microhardness of both surfaces
ChS cast iron (HB 210) — SChM cast iron (HB 252)	Cylinder liner — engine compression ring	Wear rate, friction coefficient, microhardness of both surfaces

Crankshaft — plain bearing: 40Kh steel — Br.S30 bronze

PARAMETER	OIL	BASE OIL	OIL + XADO RVS
Wear rate, µm/h	I-20	117	100
Wear rate, µm/h	M10G1	87	80
Friction coefficient	I-20	0.066	0.052
Friction coefficient	M10G1	0.048	0.043
Microhardness of 40Kh steel, MPa	I-20	5720	6420
Microhardness of 40Kh steel, MPa	M10G1	6840	7240
Microhardness of Br.S30 bronze, MPa	I-20	2540	2740
Microhardness of Br.S30 bronze, MPa	M10G1	2820	3020

I-20 industrial oil (GOST 20779-75) and M10G1 engine oil under an identical load and speed mode; microhardness of the friction surfaces measured per GOST 9450-76.

Cylinder liner — compression ring: ChS cast iron — SChM cast iron

PARAMETER	OIL	BASE OIL	OIL + XADO RVS
Wear rate, µm/h	I-20	10	8.7
Wear rate, µm/h	M10G1	9.2	8.4
Friction coefficient	I-20	0.127	0.100
Friction coefficient	M10G1	0.11	0.10
Microhardness of ChS cast iron, MPa	I-20	3100	5140
Microhardness of ChS cast iron, MPa	M10G1	3180	4280
Microhardness of SChM cast iron, MPa	I-20	3000	7240
Microhardness of SChM cast iron, MPa	M10G1	3100	4350

The hardest protective films recorded by the report were precisely those on the cast irons — the materials of the engine cylinder liner and compression ring.

Conclusions of the KhGADTU report

Section 4 of the report, “Conclusions and recommendations for implementation”, states: 1. The use of the RVS additive in the base mineral oils — I-20 industrial and M10G engine oil — reduces the wear rate of the materials by 8 to 14% and mechanical friction losses by 10 to 21%. 2. The use of the RVS additive in the base oil substantially intensifies the formation of protective wear-resistant films (secondary structures) on the friction surfaces. Particularly hard films form on cast irons (microhardness rises by 26% to 59%), then on steels — 11% — and to a lesser degree on bronzes — 7%. 3. The use of the RVS additive significantly shortens the running-in (break-in) time; this additive can serve as a running-in and modifying material. As a separate requirement, the report introduces stepped running-in: “a part, assembly or engine must be run in stepwise, from minimum loads up to operating loads”.

The results relate to model friction pairs (40Kh steel — Br.S30 bronze, ChS cast iron — SChM cast iron) on a 2070 SMT-1 friction testing machine in I-20 and M10G1 oils; the report itself states that transferring them to a specific assembly requires bench and in-service testing. RVS is an obsolete XADO designation for zero-generation compounds; the current product generation is revitalizants. The KhGADTU research report of 24.07.1998 is published in full and available for download.

Current equivalent

Revitalizant gel for compressors and bearingsCompressors · bearings · spindles
Revitalizant gel for cylinder restorationEngine cylinders, deep wear

How such units are treated: Bearings Cylinder-piston group

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