The Fatigue Strength of Large Single-Pinned and Double-Pinned Connections Made from Alloy Steel FV520B

1968 ◽  
Vol 183 (1) ◽  
pp. 563-578 ◽  
Author(s):  
D. J. White
Keyword(s):  
Fatigue Strength ◽  
Size Effect ◽  
Alloy Steel ◽  
Fatigue Tests ◽  
Mean Stress ◽  
Pinned Connections ◽  
Close Fit ◽  
Considerable Size

Fatigue tests have been conducted on single-pinned and double-pinned lugs made from alloy steel FV520B and loaded by means of 2 in diameter pins. The effects of pin fit for both clearance and interference and of various treatments were investigated. The treatments included side relieving the lug hole, bushing the bore, applying the Sulfinuz process to the lug or overstraining the lug bore. Two conditions of mean stress were investigated, namely, pulsating or repeated tension and 15 tons/in2 mean tension. Basing comparison on the fatigue strength at 30 × 106 cycles, the untreated lugs with close fit pins showed the lowest strength of all. Both clearance and interference fits were beneficial and by appropriate choice, the fatigue strength could be at least doubled and in some cases trebled. Lugs which had side relief, had been bushed, Sulfinuz treated or which had overstrained bores also gave worthwhile increases in fatigue strength and the strength ratios were generally in excess of 2. An increase in mean stress significantly reduced fatigue strength for all lugs tested, except for those with close fit or clearance fit pins. Comparing the present results with those obtained on lugs one-quarter the size, a considerable size effect is evident for some conditions, large lugs being weaker than small lugs.

Fatigue Strength of Small Pinned Connections Made from Alloy Steel Fv 520B

1967 ◽  
Vol 182 (1) ◽  
pp. 615-630 ◽  
Author(s):  
D. J. White
Keyword(s):  
Fatigue Strength ◽  
Alloy Steel ◽  
Design Method ◽  
Systematic Investigation ◽  
Fatigue Tests ◽  
Mean Stress ◽  
Interference Fit ◽  
Cadmium Plating ◽  
Engineering Sciences ◽  
Pinned Connections

Published work on pin-loaded lugs is reviewed, particular attention being given to photoelastically determined stress distributions and to results of fatigue tests for the purpose of identifying those factors that affect fatigue strength. Fatigue tests have been conducted on lugs of width 1 [Formula: see text] in made from alloy steel FV 520B and loaded by means of a [Formula: see text]-in diameter pin. A systematic investigation was made of pin fit for both clearance and interference and the effect of various treatments was investigated; these included cadmium plating the lug bore and pin, applying the ‘Sulfinuz’ process to the lug and overstraining the lug bore. Two conditions of mean stress were investigated, namely, pulsating or repeated tension and 15 tonf/in2 mean tension. Strength comparisons are based on the fatigue strength at 108 cycles, for the appropriate mean stress, of untreated lugs with exact-fit pins, these showing the lowest strength of all the lugs tested. It was found that clearance-fit pins and interference-fit pins were beneficial and with the larger values of clearance and interference tested the fatigue strength was almost doubled. Cadmium plating was ineffective while both Sulfinuz treated lugs and lugs with overstrained bores gave strength ratios of at least 1.6. An increase in mean stress from pulsating tension to 15 tonf/in2 mean tension, significantly reduced fatigue strength in most cases. On the basis of the present experimental results, the design method proposed for lugs with interference-fit pins in Royal Aeronautical Society Data Sheet A.05.02, amended by Engineering Sciences Data No. 67012, may sometimes prove to be unsafe and caution is warranted in interpreting the safe loads predicted.

Effect of Pins with Flats and Resin-Bonded Polytetrafluorethylene Coatings on the Fatigue Strength of Large Pinned Connections Made from Alloy Steel FV520B

1970 ◽  
Vol 185 (1) ◽  
pp. 709-716 ◽  
Author(s):  
D. J. White
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Thin Layer ◽  
Systematic Investigation ◽  
Fatigue Tests ◽  
Mean Stress ◽  
Strength Ratio ◽  
Critical Importance ◽  
Prolonged Fatigue ◽  
Pinned Connections

Results are presented of fatigue tests made on large lugs 4·25 in wide, loaded by means of a 2-in diameter pin. The effect on fatigue strength of a thin layer of resin-bonded p.t.f.e. stuck to the bore of the lug was studied and a systematic investigation was made of flats milled opposite to one another on the pin. The size of the flat is described by the angle (±θ) subtended by the flat at the pin centre and values from zero to +40° were covered. Two conditions of mean stress were investigated, namely, pulsating or repeated tension and 15 tonf/in2mean tension. Although resin-bonded p.t.f.e. coatings prolonged fatigue life, they did not offer a reliable means of improving fatigue strength. Pins with flats were found to be of great benefit and for ±40° flats, as compared with a round pin, the strength ratio in pulsating tension was 3·6 and, at 15 tonf/in2, mean tension was 2·9. The combination of mean stress and size of flat is of critical importance because the strength can be increased or decreased by the addition of flats to a round pin.

Effects of Extremes of Hardness and Mean Stress on Fatigue of AISI 4340 Steel in Bending and Torsion

1989 ◽  
Vol 111 (2) ◽  
pp. 119-122 ◽  
Author(s):  
W. N. Findley
Keyword(s):  
Fatigue Strength ◽  
Linear Relation ◽  
Brinell Hardness ◽  
Fatigue Tests ◽  
Mean Stress ◽  
Aisi 4340 Steel ◽  
4340 Steel ◽  
Aisi 4340

Experiments are reported for fatigue tests in bending and in torsion at hardness levels from fully annealed to fully hard and super quenched. Results indicate a linear relation between fatigue strength and Brinell hardness. The relation between bending and torsion and the effects of mean stress and size are also examined.

scholarly journals Influence of mean stress on the fatigue strength of ASTM A743 CA6NM alloy steel

2010 ◽  
Vol 4 (14) ◽  
pp. 17-26 ◽  
Author(s):  
B. Lobato da Silva ◽  
J. L. de Almeida Ferreira ◽  
F. Oliveira ◽  
J. A. Araújo
Keyword(s):  
Fatigue Strength ◽  
Alloy Steel ◽  
Mean Stress

The Size Effect in Fatigue of Plain and Notched Steel Specimens Loaded under Reversed Direct Stress

1951 ◽  
Vol 165 (1) ◽  
pp. 113-124 ◽  
Author(s):  
C. E. Phillips ◽  
R. B. Heywood
Keyword(s):  
Fatigue Strength ◽  
Size Effect ◽  
Mild Steel ◽  
Fatigue Limit ◽  
Laboratory Tests ◽  
Chromium Steel ◽  
Fatigue Tests ◽  
Strength Reduction ◽  
Engineering Practice ◽  
Nickel Chromium

The fatigue strength under reversed direct stress was ascertained for specimens of various diameters in the range from 0·19 inch to 2·4 inches, the largest diameter being determined by the capacity of the machines available. Two steels were used in this investigation—a 25-ton mild steel and a 65-ton, per cent nickel-chromium steel. The specimens were either plain or notched (transverse hole) and, as far as possible, geometrical similarity was preserved with regard to the transition radii and the diameter of the transverse hole. A few fatigue tests on other types of notch, such as a circumferential V-groove and a shoulder, were also carried out. No intrinsic size effect with either material was observed with the plain specimens. With transverse-hole specimens in mild steel, the fatigue limit was ±8·4 tons per sq. in. for specimens of 0·33 inch diameter, and 6·1 tons per sq. in. for specimens of 1·7 inches diameter, thus showing that an appreciable size effect was present. A similar size effect was found with the alloy steel specimens containing a transverse hole, and fatigue limits of ±17·1 and ±13·9 tons per sq. in. respectively were obtained for these two sizes of specimen. It is suggested that the low values of fatigue-strength reduction factors usually associated with mild steel as a result of laboratory tests do not apply to the larger sections of this material commonly employed in engineering practice.

A Study on the Development of Mach Peening for Prolonging Fatigue Life of Machine Structural Alloy Steel

2008 ◽  
Vol 580-582 ◽  
pp. 621-624
Author(s):  
Bok Kyu Lim
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Alloy Steel ◽  
Compressive Residual Stress ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Light Weight ◽  
Structural Alloy ◽  
Bending Fatigue

The light weight components, crucial in automobiles and machinery, is require hight strength. Mach peening process is one of many of techniques utilized for improving fatigue properties. From the results of rotary bending fatigue tests, the fatigue strength increases up to 129% in mach peening specimen compared with un-peening. A layer of highly compressed residual stress is obtained by mach peening. The compressive residual stress, induced by mach peening, seems to be an important factor for increasing the fatigue strength.

scholarly journals Influence of Crystal Structure of Nitride Compound Layer on Torsion Fatigue Strength of Alloy Steel

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1352 ◽  
Author(s):  
Yoshitomi Yamada ◽  
Eto Hirohito ◽  
Koji Takahashi
Keyword(s):  
Crystal Structure ◽  
Fatigue Strength ◽  
Crystal Structures ◽  
Alloy Steel ◽  
High Strength ◽  
Compound Layer ◽  
Fatigue Tests ◽  
Commercial Vehicles ◽  
Torsional Fatigue ◽  
Number Of Cycles

The demand for high-strength components for commercial vehicles has recently increased. Conventional gas nitrocarburizing has been used to increase strength and productivity of the crankshaft. A potential-controlled nitriding process was recently developed to control the crystal structure of the nitride compound layer. It has been found that this treatment improves the bending fatigue strength compared with conventional treatment, and has the potential to cope with the increase in crankshaft strength. However, the effect of torsional fatigue strength has not been studied. Therefore, in this study, the influence of the crystal structure of the nitride compound layer on torsional fatigue strength was investigated. Two kinds of test specimens with different crystal structures of the compound layer were prepared using gas nitriding treatment with controlled nitriding potential for an alloy steel bar (JIS-SCM435). Torsional fatigue tests were carried out using these test specimens. Although the compound layer of these test specimens had different crystal structures, the hardness distribution and residual stress distribution on the diffusion layer were almost the same. The relationship between stress amplitude and number of cycles to failure (S-N curve) showed that the torsional fatigue limits of the specimens were almost the same. This indicates that the crystal structure of the nitride compound layer did not affect the torsional fatigue limits, because the origin of the torsional fatigue failure is inside the specimen.

The Effect of Mean Stress on the Fatigue Strength of Magnesium Alloy ZW2

1955 ◽  
Vol 59 (537) ◽  
pp. 629-632 ◽  
Author(s):  
A. C. Low
Keyword(s):  
Fatigue Strength ◽  
Magnesium Alloy ◽  
Thick Plate ◽  
Fatigue Tests ◽  
Mean Stress ◽  
Comprehensive Investigation ◽  
Test Pieces ◽  
Formed Part ◽  
Stress Fatigue ◽  
Mean Stresses

The work reported in this Note originally formed part of a comprehensive investigation into the fatigue strength of magnesium alloy ZW2 (2 per cent. zinc, 0·65 per cent. zirconium) in sheet form. The major portion of the programme was eventually cancelled but the tests herein described are sufficiently self-contained to be repotted by themselves. Direct stress fatigue determinations were made on small round test pieces machined from ¾ in. thick plate, at mean stresses of 0, 4,000, 8,000 and 13,000 lb./in.2. Static and rotating bar fatigue tests were also made.

SANDVIK SANBAR 64

Alloy Digest ◽  
1999 ◽  
Vol 48 (10) ◽  
Keyword(s):  
Wear Resistance ◽  
Fatigue Strength ◽  
Tensile Properties ◽  
Nickel Alloy ◽  
Alloy Steel ◽  
Heat Treating ◽  
High Nickel ◽  
Hardened Condition ◽  
High Nickel Alloy

Abstract Sandvik SANDAR 64 is an air-hardening high nickel alloy steel with good response to carburizing. It has excellent fatigue strength and wear resistance in the case hardened condition. Common applications include extension and shank rods. This datasheet provides information on composition, hardness, and tensile properties. It also includes information on forming and heat treating. Filing Code: SA-503. Producer or source: Sandvik.

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