Stress Relief of Coil Springs using Fluidized Bed

2021 ◽  
Author(s):  
Andrew S. Dickinson
Keyword(s):  
Heat Treatment ◽  
Fluidized Bed ◽  
Steel Wire ◽  
Stress Relief ◽  
High Heat ◽  
Turnaround Time ◽  
Internal Stresses ◽  
High Heat Transfer ◽  
Bed Temperature ◽  
Conventional Heat Treatment

Abstract After manufacturing coil springs, internal stresses exist within the steel wire. These stresses can lead to defects and may impact the working lifespan of springs. Stress must be relieved to maximize the elastic properties of the spring alloys. Stress relief is a critical step during the manufacturing process, typically using large belt furnaces and convection ovens. The fluidized bed heat treatment system is an alternative for stress relief of small- and medium-sized coil springs. Springs are suspended in a parts basket and deposited into a fluidized bed furnace, consisting of fine aluminum oxide particles gently mixed by an upward air flow. With its high heat transfer coefficient, fluidized bed relieves the stress in coil springs in significantly less time than other conventional heat treatment methods. Bed temperature is accurately controlled using either electric heaters, with excellent thermal uniformity throughout the working area of the bed. Fluidized bed, with its advantages of uniformity and quick turnaround time, render it the best option for the rapid and efficient stress relief processing of coil springs and heat treatment of other metal components.

Optimum Time and Temperature for Stress Relief Heat Treatment of Stainless Steel Wire

1973 ◽  
Vol 52 (6) ◽  
pp. 1171-1175 ◽  
Author(s):  
Michael R. Marcotte
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Steel Wire ◽  
Stress Relief ◽  
Stainless Steel Wire ◽  
Optimum Time ◽  
Dependent Variables

With the use of springback and recovery as dependent variables, the effects of time and temperature of stress relief heat treatment of stainless steel wire were studied. Stainless steel springs exposed to a stress relief heat treatment of 750 F for 11 minutes appear to have significantly improved spring properties.

scholarly journals Heat transfer to a moving wire immersed in a gas fluidized bed furnace

2021 ◽  
Author(s):  
Antonio Tannas
Keyword(s):  
Heat Transfer ◽  
Fluidized Bed ◽  
Steel Wire ◽  
Transfer Rates ◽  
New Correlation ◽  
Bed Temperature ◽  
Molten Lead ◽  
The Difference ◽  
Considerable Work ◽  
Work Done

In order to replace hazardous molten lead baths in the heat treatment of carbon steel wire with environmentally friendly fluidized bed furnaces a better understanding is needed of their heat transfer rates. There has been considerable work done in examining heat transfer rates to large cylinders immersed in fluidized beds, and some on wire sized ones as well, but all previous studies have been conducted on static cylinders. In order to gain a deeper understanding of heat transfer rates to a moving wire immersed in a fluidized bed furnace an apparatus has been constructed to move a wire through a fluidized bed. The heat transfer rates were calculated using the difference in inlet and outlet temperatures, wire speed and the bed temperature. As predicted, correlations for static wire were found to under-predict heat transfer rates at higher wire speeds, so a new correlation was developed by modifying an existing one.

Effect of Static Bed Height on the Combustion of Rice Husk in a Fluidized Bed Combustor

2005 ◽  
Author(s):  
M. Rozainee ◽  
S. P. Ngo
Keyword(s):  
Fluidized Bed ◽  
Residence Time ◽  
Rice Husk ◽  
Bubble Formation ◽  
Combustion Process ◽  
High Heat ◽  
Transfer Rates ◽  
Bed Height ◽  
Bed Temperature ◽  
Bed Material

The combustion process is largely controlled by temperature, turbulence and residence time. When the temperature is sufficiently high so that the reaction is no longer kinetically-controlled, turbulence and residence time play a significant role. The reaction is thus diffusion-controlled. During the combustion of rice husk in a fluidized bed, the turbulence is largely governed by the mixing behavior in the inert sand bed, which in turn is governed by the bubble formation characteristics. Further, the residence time among the reactants (air and rice husk) and the heat source is also dependent on the turbulence in the bed. When all other parameters are held constant, the bubble phenomena vary according to the expanded bed height corresponding to a given static bed height. For high heat and mass transfer rates, small slowly rising bubbles are desired. Thus, the purpose of this study is to investigate the effect of static bed height on the quality of ash during the combustion of rice husk. The degree of rice husk burning in the bed could be deduced from the bed temperature as a higher bed temperature indicated that a higher portion of the rice husk feed is being burnt in the bed. Moreover, the particle size of the resulting ash is also able to give indication of the degree of rice husk burning in the bed as the turbulence arising from the bubbling action of the bed material is known to break down the char skeleton of the rice husk, thereby, resulting in ash with finer size. From this study, the static bed height of 0.5 DC was found to give the lowest residual carbon content in the ash (1.9 wt%) and the highest bed temperature (670°C) among the other range of static bed heights investigated.

Study on Pollutants Emission Characteristic of Coal Gasification in a Fluidized Bed Test Rig

2005 ◽  
Author(s):  
Zhaoping Zhong ◽  
Baosheng Jin ◽  
Yaji Huang ◽  
Hongcang Zhou ◽  
Davide Ross ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Coal Gasification ◽  
Local Maximum ◽  
High Heat ◽  
Relative Mass ◽  
Feed Ratio ◽  
Emission Characteristic ◽  
Test Rig ◽  
Coal Syngas ◽  
Bed Temperature

This paper presents the results of coal gasification in a fluidized bed test rig of Xuzhou bituminous coal. The diameter of the fluidized bed combustor is 0.1m and the height is 4.22m. The bed temperature is maintained by a method of high temperature flue gas interline heating to overcome high heat losses associated with a oil burner. Test results are reported for variations in the bed temperature, air to coal, steam to coal and Ca to S ratio and their influence on gas yields and desulphurization efficiency. The distribution of polycyclic aromatic hydrocarbons (PAHs) and heavy metal trace elements into the char and syngas are also presented. The molar contents for CH4 and H2 in the coal syngas are found to decrease with increasing air to coal feed ratio from 2.5 to 5, while the content of CO shows little variation. Increasing the steam to coal feed ratio from 0.4 to 0.65 results in all three of the main gas components measured to form a local maximum content at a steam/coal feed ratio of 0.55. The efficiency of desulphurization improves as the ratio of Ca to S, air to coal and the bed temperature are increased, while decreasing with increasing steam to coal feed ratios. The volatile trace element species in decreasing order of relative mass ratio released into the gas phase are Hg, Se, As, Co, Cr, Cd, Cu, and Zn. Besides Hg, Se, and As, for all other trace heavy metals the majority of their mass distribution remains within the char with the proportion contained within char always greater than their combined yields in the coal syngas and slag. The total PAHs in the coal syngas is greater than that contained in the original coal and this indicates that PAHs are formed during the coal gasification process.

scholarly journals Heat transfer to a moving wire immersed in a gas fluidized bed furnace

2021 ◽  
Author(s):  
Antonio Tannas
Keyword(s):  
Heat Transfer ◽  
Fluidized Bed ◽  
Steel Wire ◽  
Transfer Rates ◽  
New Correlation ◽  
Bed Temperature ◽  
Molten Lead ◽  
The Difference ◽  
Considerable Work ◽  
Work Done

In order to replace hazardous molten lead baths in the heat treatment of carbon steel wire with environmentally friendly fluidized bed furnaces a better understanding is needed of their heat transfer rates. There has been considerable work done in examining heat transfer rates to large cylinders immersed in fluidized beds, and some on wire sized ones as well, but all previous studies have been conducted on static cylinders. In order to gain a deeper understanding of heat transfer rates to a moving wire immersed in a fluidized bed furnace an apparatus has been constructed to move a wire through a fluidized bed. The heat transfer rates were calculated using the difference in inlet and outlet temperatures, wire speed and the bed temperature. As predicted, correlations for static wire were found to under-predict heat transfer rates at higher wire speeds, so a new correlation was developed by modifying an existing one.

Combustion and Emission Performance of a Hog Fuel Fluidized Bed Boiler With Addition of Tire Derived Fuel

2003 ◽  
Author(s):  
Wenli Duo ◽  
Ibrahim Karidio ◽  
Larry Cross ◽  
Bob Ericksen
Keyword(s):  
Fluidized Bed ◽  
Energy Content ◽  
Steel Wire ◽  
Stable Operation ◽  
Particulate Emissions ◽  
Complete Combustion ◽  
Design Capacity ◽  
Bed Temperature ◽  
Stack Emissions ◽  
The Impact

Salt-laden hog fuel (wood waste) is burnt in a fluidized bed boiler converted from a travelling grate boiler to generate steam for a specialty paper mill. The converted boiler has a design capacity of 156 t/h of steam from hog and actual generation has varied from 76 to 107% of the design capacity. The conversion has resulted in more stable operation, more complete combustion, less ash production, reduced boiler maintenance, and lower fossil fuel consumption. Tire derived fuel (TDF) is used as a supplementary fuel. With an energy content of 33 GJ/t for TDF, as compared to 8 GJ/t for wet hog, addition of 2–5% TDF by weight increased the bed temperature by an average of 55°C, stabilized and improved the combustion of low quality hog and high moisture content sludge. The impact of TDF addition was studied in detail. Stack emissions were tested and bottom and fly ash samples were analyzed. Although TDF contains 1% zinc and 5 to 7% steel wire, addition of TDF did not affect total particulate emissions from the boiler. SO2 emissions were increased due to the high sulfur content of TDF (1.6%). A good correlation was obtained from the test results, showing that the addition of TDF resulted in a reduction in both the total formation and the stack emissions of dioxins and furans.

scholarly journals Solid-State Transformation of an Additive Manufactured Inconel 625 Alloy at 700 °C

2021 ◽  
Vol 11 (18) ◽  
pp. 8643
Author(s):  
Fan Zhang ◽  
Jan Ilavsky ◽  
Greta Lindwall ◽  
Mark R. Stoudt ◽  
Lyle E. Levine ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Solid State ◽  
Stress Relief ◽  
Ex Situ ◽  
Inconel 625 ◽  
Internal Stresses ◽  
State Transformation ◽  
Solid State Transformation ◽  
Δ Phase

Inconel 625, a nickel-based superalloy, has drawn much attention in the emerging field of additive manufacturing (AM) because of its excellent weldability and resistance to hot cracking. The extreme processing condition of AM often introduces enormous residual stress (hundreds of MPa to GPa) in the as-fabricated parts, which requires stress-relief heat treatment to remove or reduce the internal stresses. Typical residual stress heat treatment for AM Inconel 625, conducted at 800 °C or 870 °C, introduces a substantial precipitation of the δ phase, a deleterious intermetallic phase. In this work, we used synchrotron-based in situ scattering and diffraction methods and ex situ electron microscopy to investigate the solid-state transformation of an AM Inconel 625 at 700 °C. Our results show that while the δ phase still precipitates from the matrix at this temperature, its precipitation rate and size at a given time are both smaller when compared with their counterparts during typical heat treatment temperatures of 800 °C and 870 °C. A comparison with thermodynamic modeling predictions elucidates these experimental findings. Our work provides the rigorous microstructural kinetics data required to explore the feasibility of a promising lower-temperature stress-relief heat treatment for AM Inconel 625. The combined methodology is readily extendable to investigate the solid-state transformation of other AM alloys.

Combustion and Emission Performance of a Hog Fuel Fluidized Bed Boiler With Addition of Tire Derived Fuel

2006 ◽  
Vol 129 (1) ◽  
pp. 42-49 ◽  
Author(s):  
Wenli Duo ◽  
Ibrahim Karidio ◽  
Larry Cross ◽  
Bob Ericksen
Keyword(s):  
Fluidized Bed ◽  
Energy Content ◽  
Steel Wire ◽  
Stable Operation ◽  
Particulate Emissions ◽  
Complete Combustion ◽  
Design Capacity ◽  
Bed Temperature ◽  
Stack Emissions ◽  
The Impact

Salt-laden hog fuel (wood waste) is burnt in a fluidized bed boiler converted from a traveling grate boiler to generate steam for a specialty paper mill. The converted boiler has a design capacity of 156t∕h of steam from hog and actual generation has varied from 76% to 107% of the design capacity. The conversion has resulted in more stable operation, more complete combustion, less ash production, reduced boiler maintenance, and lower fossil fuel consumption. Tire derived fuel (TDF) is used as a supplementary fuel. With an energy content of 31GJ∕t for TDF, as compared to 8GJ∕t for wet hog, addition of 2%–5% TDF by weight increased the bed temperature by an average of 55°C, stabilized and improved the combustion of low quality hog and high moisture content sludge. The impact of TDF addition was studied in detail. Stack emissions were tested and bottom and flyash samples were analyzed. Although TDF contains an average of 1.6% zinc and 9.2% steel wire by weight, addition of TDF did not affect total particulate emissions from the boiler. SO2 emissions were increased due to the high sulfur content of TDF (1.4%), while NOx emissions were reduced. A good correlation was obtained from the test results, showing that the addition of TDF resulted in a reduction in both the total formation and the stack emissions of dioxins and furans.

Choosing a Suitable Heat Treatment Regime for Stress-Relief and Microstructure Stabilization of Ti6Al4V Alloy 3D-printed by SLM Method

2020 ◽  
Vol 403 ◽  
pp. 11-18
Author(s):  
Michaela Roudnicka ◽  
Eduardo Alarcon Tarquino ◽  
Dalibor Vojtech
Keyword(s):  
Heat Treatment ◽  
3D Printing ◽  
Stress Relief ◽  
Ti6al4v Alloy ◽  
Treatment Regime ◽  
Internal Stresses ◽  
Suitable Heat Treatment ◽  
Heat Treatment Regime ◽  
3D Printed ◽  
The Subject

During the processing of Ti6Al4V alloy by a 3D printing method SLM (selective laser melting), high internal stresses are developed in the material as a result of high temperature gradients between microvolumes of the powder melted at a given time and the already solidified material. Cooling rates thus reach up to the order of 108 °C·s-1. At such rates, a diffusionless martensitic transformation occurs, which also contributes to internal stresses in the material. High internal stresses can be a problem already during production; they can manifest themselves by cracking of products, deformations of thin parts, etc. Even in defectless products, internal stresses negatively affect their properties; in particular, they reduce ductility. Therefore, it is desirable to include a heat treatment after the 3D printing, which would reduce the stresses and transform the metastable martensitic structure into a stable one. As a result of the heat treatment, the ductility increases at the expense of strength. The subject of this paper is to find such heat treatment regime that provides the best combination of mechanical properties.

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