Dimensional Changes of Nb3Sn, Nb3Al and Bi2Sr2CaCu2O8 Conductors During Heat Treatment and Their Implication for Coil Design

Author(s):  
D. R. Dietderich ◽  
J. R. Litty ◽  
R. M. Scanlan
2013 ◽  
Vol 535-536 ◽  
pp. 271-274
Author(s):  
Jeongsuk Lim ◽  
Sunghoon Kang ◽  
Young Seon Lee

The dimensional change of tooth profile by heat treatment of helical gear was investigated by experimental and numerical approaches. Especially, the three-dimensional elasto-plastic finite element (FE) simulation was adopted to analyze the elastic deformation during load, unloading, ejecting of workpiece. Quenching simulation was also carried out to investigate the change of tooth profile on the forged gear. In experiments, the amount of elastic deformation of the forged gear was quantitatively determined by comparing the tooth profiles on the forged gear and die. The dimensional change of the forged gear tooth after quenching was also evaluated from the comparision of the cold forged and quenched gear teeth. From experimental works, it was found that the amounts of dimensional changes after forging and quenching of helical gear are 10 and 10 μm, respectively.


Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4721
Author(s):  
Amalie Gunnarshaug ◽  
Maria-Monika Metallinou ◽  
Torgrim Log

Processing highly flammable products, the oil and gas (O&G) industry can experience major explosions and fires, which may expose pressurized equipment to high thermal loads. In 2020, oil fires occurred at two Norwegian O&G processing plants. To reduce the escalation risk, passive fire protection may serve as a consequence-reducing barrier. For heat or cold conservation, equipment and piping often require thermal insulation, which may offer some fire protection. In the present study, a representative thermal insulation (certified up to 700 °C) was examined with respect to dimensional changes and thermal transport properties after heat treatment to temperatures in the range of 700 °C to 1200 °C. Post heat treatment, the thermal conductivity of each test specimen was recorded at ambient temperature and up to 700 °C, which was the upper limit for the applied measurement method. Based on thermal transport theory for porous and/or amorphous materials, the thermal conductivity at the heat treatment temperature above 700 °C was estimated by extrapolation. The dimensional changes due to, e.g., sintering, were also analyzed. Empirical equations describing the thermal conductivity, the dimensional changes and possible crack formation were developed. It should be noted that the thermal insulation degradation, especially at temperatures approaching 1200 °C, is massive. Thus, future numerical modeling may be difficult above 1150 °C, due to abrupt changes in properties as well as crack development and crack tortuosity. However, if the thermal insulation is protected by a thin layer of more robust material, e.g., passive fire protection to keep the thermal insulation at temperatures below 1100 °C, future modeling seems promising.


2006 ◽  
Vol 514-516 ◽  
pp. 702-706
Author(s):  
Sasan Yazdani

Control and prediction of the dimensional changes (DC) during austempering heat treatment of ductile iron is difficult because many factors influence this behavior. In the present work cylindrical specimens of ductile iron were used to study the effect of austenitizing temperature, austempering time, temperature, and prior microstructure on DC. The results show that DC increases with increasing austenitizing temperature in the range of 850 to 950°C with a fully ausferrite microstructure. Evaluation of different combinations of ferrite and pearlite contents in prior microstructure indicates that a fully ferritic structure has the highest DC. In addition, results show that by lowering austempering temperature from 400 to 250°C, DC increases.


2011 ◽  
Vol 690 ◽  
pp. 210-213 ◽  
Author(s):  
Serge Gavras ◽  
Su Ming Zhu ◽  
Mark A. Easton ◽  
Mark A. Gibson ◽  
Jian Feng Nie

In this study effects of heat treatments on the creep resistance at 177°C/90MPa of a high-pressure die-cast Mg-2.70La-1.50Y (wt.%) alloy were examined. It was found that ageing at 160°C for 24 h (T5) or a solution treatment at 520°C for 1 h (T4) improved creep resistance and caused no blistering on the surface or dimensional changes to the die-cast specimens. TEM was used to characterize the microstructures of heat-treated samples. Improvements to creep resistance might be attributed to the pinning or otherwise retarding of dislocation motion by precipitates and/or solute atoms during creep.


2020 ◽  
Vol 3 (3) ◽  
pp. 126-134
Author(s):  
Eko Julianto ◽  
Sunaryo Sunaryo ◽  
Elkana Bilak Lopo

The purpose of this study was to determine the shape change characteristics of float sheet glass using heat treatment experiments on its surface. This involved the use of a float glass type with a thickness of 5 mm, a width of 840 mm, and length of 1350 mm as the test specimen and the heat transfer experiments and treatment were conducted through conduction with the heat distribution recorded to be between 34 °C and 600 °C at every 5 minutes within 60 minutes in a heating furnace. The analysis focused on the characteristics of the glass surface exposed to fire with emphasis placed on the temperature during the deflection changes in the entire glass surface, the dimensional changes at the edges of the glass which follow the glass printing pattern, and the changes in temperature on the upper and lower surfaces of the curved glass mold. The results showed the existence of a very clear change in each temperature or conduction heat when the shape of the glass is changed to curve with the ideal shape observed to have changed at a temperature of 482.50 °C. Moreover, dimensional changes were 1.0427 m2 and the variations in the temperature were 107.55 °C and the continuous increase in the heat was to have led to a faster change in the glass shape by 11.2°. This, therefore, means a higher temperature or room temperature affects the firing rate of glass bending and also increases the rate of heat absorption.


2010 ◽  
Vol 638-642 ◽  
pp. 829-834 ◽  
Author(s):  
Chun Yan Nan ◽  
Derek O. Northwood ◽  
Randy J. Bowers ◽  
Xi Chen Sun

Carbonitriding is a metallurgical surface modification technique that is widely used in the automotive industry to increase surface hardness and wear resistance. Given the problems associated with carbonitriding, such as dimensional distortion, oxidation and non-uniform surface hardness, nitrocarburizing has been proposed as an alternative heat treatment method to improve the surface characteristics. The major advantages of ferritic nitrocarburizing are the minimal dimensional changes and distortion due to the low process temperature at which no phase transformations occur. This increases productivity and product quality, and decreases costs. The focus of this study was to determine the effects of carbonitriding and ferritic nitrocarburizing processes on the dimensional changes and residual stresses in a steel used for automotive applications. Navy C-ring specimens and prototype stamped parts made from SAE 1010 plain carbon steel were used in the testing. Gas, vacuum and ion ferritic nitrocarburizing processes with different heat treatment parameters were investigated. X-ray diffraction techniques were used for the residual stresses evaluation and surface phase analysis of the specimens.


2013 ◽  
Vol 23 (3) ◽  
pp. 9000404-9000404 ◽  
Author(s):  
Dustin McRae ◽  
Robert Walsh

The performance of Nb3Sn composite superconducting wire is highly dependent on its strain state, which is difficult to predict or measure accurately. There is limited data in the literature on Nb3Sn or conduit alloys for the thermal expansion/contraction that occurs during reaction heat treatments. Thermal expansion measurements of two contemporary Nb3Sn wires and two conduit alloys-316LN and JK2LB-are taken individually during reaction heat treatments in a wide temperature range (4-1200 K) dilatometer system at the NHMFL. The measurements observed here are compared with the existing data and predicted models. This work significantly increases the available data for Nb3Sn superconductors and conduit alloys that can be used in magnet design and predictive modeling.


Sign in / Sign up

Export Citation Format

Share Document