Load-carrying Properties Research Articles

Fatigue strength evaluation of spot-welded joints for car body structures.

Fatigue strength design techniques for spot-welded car body structures are studied. The load-carrying property per spot of a spot-welded structure is estimated by the finite element method. The validity of this method is confirmed by fatigue strength design procedure for spot-welded car body structures is shown.

Experimental thawing of permafrost soils in bases of reconstructed main building of the Chita-I Thermoelectric Power Plant

1. Compaction of thawed soils takes place directly during the thawing process or in the first 10–35 days after it. The thawed soils do not require subsequent compaction and, as regards the load-carrying properties, they are comparable to similar rocks in a naturally thawed state.

The load-carrying properties of certain S-alkylisothioamides and their effectiveness as extreme pressure lubricant additives

Certain S-alkylisothioamides were synthesized and their load-carrying capacities assessed using a Seta Shell four-ball machine. S-benzylisothiobenzamide was found to be potentially attractive.

The Effect of Chemical Structure on the Load-Carrying and Adsorption Properties of Dialkyl Phosphites

The load-carrying properties of a range of dialkyl phosphites have been examined under antiwear (AW) and antiscuff conditions using the four-ball machine. Adsorption/reaction of these compounds with iron surfaces has also been carried out. The results showed that both the load-carrying and adsorption/reaction properties of these dialkyl phosphites are markedly affected by the chain length and structure of the alkyl group. A mechanism of action of dialkyl phosphites is proposed which not only provides an explanation for both sets of observations but also highlights the difference in load-carrying action of dialkyl phosphites compared to the corresponding phosphates. Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference held in Atlanta, Georgia, October 16–18, 1973

Lubrication of Sliding/Rolling Contacts Using a Disc Machine of Novel Design

A new type of disc machine has been developed which may be used for evaluation of the load-carrying properties of lubricants. Commissioning tests revealed that it possesses some advantages over more conventional machines, notably in terms of operating range and flexibility. Examination of critical temperature and film thickness failure criteria suggested that both approaches may be used to explain the occurrence of lubricant film breakdown. The machine has shown its ability to differentiate between oils of different load-carrying properties, and encouraging agreement with the IAE gear machine, when operated under similar conditions, has been obtained.

The effect of chemical structure on the load-carrying properties of amine phosphates

The load-carrying properties of a range of dialkyl phosphates and their alkylamine salts were assessed using the four-ball machine. The antiwear and extreme-pressure properties of these additives were found to be markedly dependent on the structure of both the acid phosphate and the amine. Similar trends were not observed for the dithiophosphate analogues. Possible explanations for these results are presented.

On the dynamic behaviour of machine tool slideway (1st report, characteristics of static friction in stick-slip motion): KATO, S., MATSUBAYASHI, T. Bulletin of the Japan Society of Mechanical Engineers, Vol 13, No 55 (Jan 1970) pp 170–179

A range of diester disulphides was synthesised and their extreme-pressure and antiwear properties assessed using the Four-Ball machine. The diester disulphides had better antiwear properties, and poorer extreme-pressure properties than the corresponding unsubstituted disulphides. Dialkoxy substituted disulphides had similar extreme-pressure and antiwear properties to unsubstituted disulphides. Maximum antiwear protection at low additive concentration, followed by subsequent increase in wear with increasing concentration, was obtained for diester disulphides [-S(-CH2)nCOOC2H5]2 where n = 1, 2 and 3, but not when n = 5, 10. Explanations for these results are given and these are supported by heats of adsorption and electron probe microanalysis studies. It is suggested that the prime requirement for improving the antiwear properties of organo-sulphur compounds is the presence of strongly adsorbing groups at both ends of the molecule. These results also highlight the fact that the load-carrying properties of additives for one application can be improved only at the expense of its possible use in other fields.

Wear behaviour of polybenzimidazole bonded solid film lubricants: HUBBELL, R.D., McCONNELL, B.D. Transactions of the American Society of Mechanical Engineers, Journal of Lubrication Technology, Vol 92, Series F, No 2 (Apr 1970) pp 252–257

A range of diester disulphides was synthesised and their extreme-pressure and antiwear properties assessed using the Four-Ball machine. The diester disulphides had better antiwear properties, and poorer extreme-pressure properties than the corresponding unsubstituted disulphides. Dialkoxy substituted disulphides had similar extreme-pressure and antiwear properties to unsubstituted disulphides. Maximum antiwear protection at low additive concentration, followed by subsequent increase in wear with increasing concentration, was obtained for diester disulphides [-S(-CH2)nCOOC2H5]2 where n = 1, 2 and 3, but not when n = 5, 10. Explanations for these results are given and these are supported by heats of adsorption and electron probe microanalysis studies. It is suggested that the prime requirement for improving the antiwear properties of organo-sulphur compounds is the presence of strongly adsorbing groups at both ends of the molecule. These results also highlight the fact that the load-carrying properties of additives for one application can be improved only at the expense of its possible use in other fields.

The load-carrying properties of diester disulphides

A range of diester disulphides was synthesised and their extreme-pressure and antiwear properties assessed using the Four-Ball machine. The diester disulphides had better antiwear properties, and poorer extreme-pressure properties than the corresponding unsubstituted disulphides. Dialkoxy substituted disulphides had similar extreme-pressure and antiwear properties to unsubstituted disulphides. Maximum antiwear protection at low additive concentration, followed by subsequent increase in wear with increasing concentration, was obtained for diester disulphides [-S(-CH 2) nCOOC 2H 5] 2 where n = 1, 2 and 3, but not when n = 5, 10. Explanations for these results are given and these are supported by heats of adsorption and electron probe microanalysis studies. It is suggested that the prime requirement for improving the antiwear properties of organo-sulphur compounds is the presence of strongly adsorbing groups at both ends of the molecule. These results also highlight the fact that the load-carrying properties of additives for one application can be improved only at the expense of its possible use in other fields.

The Load-Carrying Properties of Metal Dialkyl Dithiophosphates: The Effect of Chemical Structure

The extreme pressure (e.p.) and mixed lubrication or antiwear (a.w.) properties of a range of metal dialkyl dithiophosphates have been examined using the four ball machine. The results show that the nature of the metal atom is a major factor in determining these properties, and that the factors governing e.p. and a.w. activities are different. Thus the order of decreasing e.p. activity is Bi(III) > Ag(I), Pb(II) > Sb(III), Sn(II) ≥ Cd(II), Fe(III), Ni(II) > Zn(II), whilst the order of decreasing a.w. activity is Cd(II), Zn(II), Ni(II) ≥ Fe(III) > Ag(I) > Pb(II) > Sb(III), Sn(II) > Bi(III) for a series of 4-methylpentyl-2 and n-hexyl salts. The nature of the alkyl group has a lesser effect on either e.p. or a.w. properties. Possible explanations for these results are presented.

Load-Carrying Properties of Metal Dialkyl Dithiophosphates: Application of Electron Probe Microanalysis

The surface topography and the nature of the surface layer of wear scars obtained with Bi(III), Pb(II), Cd(II), Ni(ll), and Zn(II) di-(4-methylpentyl-2) dithiophosphates, using the four-ball machine, have been studied using an electron probe microanalysis (EPMA) technique. The results show that the nature of the dithiophosphate markedly affects the surface topography, element content, and distribution of the wear scar in both the extreme pressure and mixed lubrication or antiwear regions. The implication of these EPMA results on the load-carrying mechanism of metal dialkyl dithiophosphates is discussed.

Laboratory Tests with Turboprop Lubricants

The Modified SAE EP Lubricants Testing Machine and the McKee EP Lubricants Testing Machine use two contacting cylindrical test cups which are rotated at different speeds under load to give combined rolling and rubbing action typical of gear teeth. With these machines methods were developed for evaluating the anti-wear and the load-carrying properties of turboprop lubricants. Data are presented for 31 oils tested on the above machines, and for 25 of these oils also tested for stability at high temperatures on the McKee Oil Stability Apparatus. Contributed to the American Society of Lubrication Engineers by the author. Manuscript received 1 October 1957.