scholarly journals Influence of Corrosion on Fatigue of the Fastening Bolts

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1485
Author(s):  
Maciej B. Lachowicz ◽  
Marzena M. Lachowicz
Keyword(s):  
Steel Substrate ◽  
Fatigue Cracks ◽  
Zinc Coating ◽  
High Strength ◽  
Operating Conditions ◽  
Cyclic Loads ◽  
Concentration Cell ◽  
High Strength Bolt ◽  
Actual Operating ◽  
Radial Cracks

The aim of the present work was to evaluate high-strength bolt corrosion fatigue based on metallographic examinations. The conducted tests were focused on the analysis of damaged martensitic bolts. It was found that the combined presence of cyclic loads and a corrosive environment was the cause of the accelerated fatigue of the fastening bolts. The tests carried out indicate that the actual operating conditions were different than expected. The corrosion contributed to the loosening of the bolts and initiation of fatigue cracks in the bolt threads. Further damage of the galvanized bolts was caused by fatigue crack growth in their threaded part that propagated towards the centre of the material. Cracks in the zinc coating were transferred to the steel substrate. The corrosion was favored by the oxygen concentration cell and numerous radial cracks appear in the zinc coating. The vibrations accompanying the operation of the wind tower led to their further propagation and the formation of the fatigue fracture in one of the bolts.

Processing strategy for high strength Ni-based hybrid composite clad on SS 316L steel through microwave heating

2021 ◽  
pp. 095440542110213
Author(s):  
Sarbjeet Kaushal ◽  
Satnam Singh ◽  
Dheeraj Gupta
Keyword(s):  
Sliding Wear ◽  
Steel Surface ◽  
Steel Substrate ◽  
Microstructural Analysis ◽  
High Strength ◽  
Phase Changes ◽  
Microwave Exposure ◽  
Pull Out ◽  
316L Steel ◽  
Microwave Applicator

Processing of nickel-based high strength composites and alloys is a difficult and thought-provoking task. In this work, a strategy of heating through microwaves radiation is utilized to process the high strength hybrid Ni-based composite clad on SS 316L steel surface containing 15% (WC-8Co) and 5% Mo. The premixed composite powder was placed on the steel surface and irradiated with domestic microwave applicator having 2.45 GHz fixed frequency and 900 W power. The hybrid clad was successfully developed within 12–15 min of microwave exposure. The processed clad was subjected to various metallurgical and mechanical characterizations to understand the microstructures and phase changes. Microstructural analysis study revealed that the clad of ∼0.85 mm thickness was obtained and presence of dispersed reinforced particles of WC-8Co and Mo in nickel matrix were observed. Some inter-metallic phases of W2C, Ni2Mo4C, Ni4W and NiSi2 were observed in the clad. The average microhardness of the composite clad was712 ± 58 HV. The microwave processed clad exhibited a flexural strength of 852 ± 6 MPa with deformation index of 35 × 10−5 mm/N. Further, the sliding wear study revealed that the sliding velocity of 1.0 m/s favoured the formation of oxide tribo layers. The various mechanisms of wear revealed by the analysis of worn-out surfaces were abrasion, adhesion, surface pull-out and deformation of surfaces. The microwave processed clad revealed significant improvement in wear resistance in comparison to the steel substrate.

scholarly journals Electrochemical treatment of high strength chrome bathwater: A comparative study for best-operating conditions

2021 ◽  
pp. 100093
Author(s):  
Vishakha Gilhotra ◽  
Rekha Yadav ◽  
Aditi Sugha ◽  
Laxmi Das ◽  
Ashutosh Vashisht ◽  
...  
Keyword(s):  
Comparative Study ◽  
High Strength ◽  
Electrochemical Treatment ◽  
Operating Conditions

Constant-amplitude fatigue behavior of M24 high-strength bolt of end-plate flange connection

Structures ◽  
2021 ◽  
Vol 34 ◽  
pp. 2041-2053
Author(s):  
Jinfeng Jiao ◽  
Zhanxiang Liu ◽  
Qi Guo ◽  
Yong Liu ◽  
Honggang Lei
Keyword(s):  
Fatigue Behavior ◽  
High Strength ◽  
Constant Amplitude ◽  
Flange Connection ◽  
End Plate ◽  
High Strength Bolt

THE VALUE OF FINE BUBBLE DIFFUSER TESTING UNDER ACTUAL OPERATING CONDITIONS IN A HIGHLY INDUSTRIAL WASTEWATER

2005 ◽  
Vol 2005 (14) ◽  
pp. 2232-2247
Author(s):  
Michael S. Demko ◽  
Frank Coughenour ◽  
John J. Pacifici ◽  
Sam Jeyanayagam ◽  
David T. Redmon
Keyword(s):  
Industrial Wastewater ◽  
Operating Conditions ◽  
Actual Operating ◽  
Fine Bubble

Capability of martensitic low transformation temperature welding consumables for increasing the fatigue strength of high strength steel joints

2020 ◽  
Vol 62 (9) ◽  
pp. 891-900
Author(s):  
Jonas Hensel ◽  
Arne Kromm ◽  
Thomas Nitschke-Pagel ◽  
Jonny Dixneit ◽  
Klaus Dilger
Keyword(s):  
Residual Stress ◽  
Phase Transformation ◽  
Fatigue Strength ◽  
High Strength Steel ◽  
Transformation Temperature ◽  
Fatigue Cracks ◽  
High Strength ◽  
Filler Material ◽  
Phase Transformation Temperature ◽  
Filler Materials

Abstract The use of low transformation temperature (LTT) filler materials represents a smart approach for increasing the fatigue strength of welded high strength steel structures apart from the usual procedures of post weld treatment. The main mechanism is based on the effect of the low start temperature of martensite formation on the stress already present during welding. Thus, compressive residual stress formed due to constrained volume expansion in connection with phase transformation become highly effective. Furthermore, the weld metal has a high hardness that can delay the formation of fatigue cracks but also leads to low toughness. Fundamental investigations on the weldability of an LTT filler material are presented in this work, including the characterization of the weld microstructure, its hardness, phase transformation temperature and mechanical properties. Special attention was applied to avoid imperfections in order to ensure a high weld quality for subsequent fatigue testing. Fatigue tests were conducted on the welded joints of the base materials S355J2 and S960QL using conventional filler materials as a comparison to the LTT filler. Butt joints were used with a variation in the weld type (DY-weld and V-weld). In addition, a component-like specimen (longitudinal stiffener) was investigated where the LTT filler material was applied as an additional layer. The joints were characterized with respect to residual stress, its stability during cyclic loading and microstructure. The results show that the application of LTT consumables leads to a significant increase in fatigue strength when basic design guidelines are followed. This enables a benefit from the lightweight design potential of high-strength steel grades.

The Impact of Electric Hybrid Compressor to Make Transport Environmentally Friendly

2013 ◽  
Vol 391 ◽  
pp. 207-212
Author(s):  
Maciej Bajerlein
Keyword(s):  
Energy Consumption ◽  
Operating Conditions ◽  
Vehicle Speed ◽  
Suspension Systems ◽  
Actual Operating ◽  
Vehicle Operation ◽  
Total Energy Balance ◽  
The Impact ◽  
Road Emission ◽  
Speed Engine

This paper presents the investigations, whose aim was to determine the influence of the operation of electric and mechanical compressors on the energy consumption of city buses in public transport. The tests were performed on pneumatic systems used in city transit vehicles whose underlying component is a compressor generating pressure for the brake and suspension systems. Owing to the application of a portable analyzer - SEMTECH DS the emissions (with a secondly resolution) of CO, HC, NOx, CO2 in the exhaust gases were measured. The on-road emission tests were performed in the actual operating conditions in SORT driving tests. These tests reflect the actual vehicle operation in a real task through preset procedures of their realization and measurements determining the energy consumption and exhaust emissions or the influence of the vehicle accessories and all variables (vehicle speed, engine load, acceleration or distance covered) on the total energy balance. The on-road tests were performed on a runway of the Bednary airstrip in Poland.

Ambient Condition Effects on NOx and CO Emissions From Process Heaters

2008 ◽  
Author(s):  
Wesley R. Bussman ◽  
Charles E. Baukal
Keyword(s):  
Atmospheric Pressure ◽  
Ambient Air ◽  
Operating Conditions ◽  
Nox Emissions ◽  
Ambient Conditions ◽  
Fuel Gas ◽  
Natural Draft ◽  
Actual Operating ◽  
Wide Range ◽  
Pollution Emissions

Because process heaters are typically located outside, their operation is subject to the weather. Heaters are typically tuned at a given set of conditions; however, the actual operating conditions may vary dramatically from season to season and sometimes even within a given day. Wind, ambient air temperature, ambient air humidity, and atmospheric pressure can all significantly impact the O2 level, which impacts both the thermal efficiency and the pollution emissions from a process heater. Unfortunately, most natural draft process burners are manually controlled on an infrequent basis. This paper shows how changing ambient conditions can considerably impact both CO and NOx emissions if proper adjustments are not made as the ambient conditions change. Data will be presented for a wide range of operating conditions to show how much the CO and NOx emissions can be affected by changes in the ambient conditions for fuel gas fired natural draft process heaters, which are the most common type used in the hydrocarbon and petrochemical industries. Some type of automated burner control, which is virtually non-existent today in this application, is recommended to adjust for the variations in ambient conditions.

Sign in / Sign up

Export Citation Format

Share Document