Thermal Forming of Sheet and Plate

2006 ◽  
pp. 424-428
Keyword(s):  
Thermal Forming

Effects of inductor patterns on temperature and deformation behavior of ship hull plate by induction heating

2018 ◽  
Vol 232 (23) ◽  
pp. 4371-4389
Author(s):  
Shuiming Zhang ◽  
Cungen Liu ◽  
Xuefeng Wang ◽  
Zhi Yang
Keyword(s):  
Induction Heating ◽  
Opposite Direction ◽  
Thermal Deformation ◽  
Transient Analysis ◽  
Ship Hull ◽  
Temperature Dependent ◽  
Thermal Forming ◽  
Ship Hull Plate ◽  
Heating Direction ◽  
Transverse Shrinkage

This paper mainly investigated the effects of different inductor patterns on thermal forming behavior of ship hull plate by moving induction heating. Alternately-coupled electromagnetic-thermal analysis procedure considering temperature-dependent material properties was firstly implemented at each moving step of inductor, followed with uncoupled thermal-mechanical transient analysis to obtain corresponding thermal deformation. Then temperature distribution, dimensions (breadth b and depth h) of heat-affected zone, and deformation obtained from codirectional current-carrying inductor with no gap and opposite-direction current-carrying inductor with gap were compared, respectively. And effects of heating directions and distance T2 of ODIG were also analyzed. It turns out that codirectional current-carrying inductor with no gap can generate much larger transverse shrinkage at 1.8–2.5 mm/s than opposite-direction current-carrying inductor with gap, otherwise smaller at 3.2–4.0 mm/s, likewise larger temperature gradient at 1.8–4.0 mm/s and thus larger bending angular deformation. Besides, heating direction “Out” can generate larger deformation than “In” and deformation for opposite-direction current-carrying inductor with gap can be effectively improved through adjusting distance T2 until 13 mm. These indicate that adopting appropriate inductor patterns, heating direction and distance T2 of opposite-direction current-carrying inductor with gap can significantly improve thermal forming behavior.

An approach to reduce stress and defects: a hybrid process of laser cladding deposition and shot peening

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xiaoyu Zhang ◽  
Dichen Li ◽  
Jiale Geng
Keyword(s):  
Tensile Stress ◽  
Compressive Stress ◽  
Laser Cladding ◽  
Shot Peening ◽  
Hybrid Process ◽  
Layer By Layer ◽  
Residual Tensile Stress ◽  
Forming Process ◽  
Content Type ◽  
Thermal Forming

Purpose Laser cladding deposition is limited in industrial application by the micro-defects and residual tensile stress for the thermal forming process, leading to lower fatigue strength compared with that of the forging. The purpose of this paper is to develop an approach to reduce stress and defects. Design/methodology/approach A hybrid process of laser cladding deposition and shot peening is presented to transform surface strengthening technology to the overall strengthening technology through layer-by-layer forming and achieve enhancement. Findings The results show that the surface stress of the sample formed by the hybrid process changed from tensile stress to compressive stress, and the surface compressive stress introduced could reach more than four times the surface tensile stress of the laser cladding sample. At the same time, internal micro-defects such as pores were reduced. The porosity of the sample formed by the hybrid process was reduced by 90.12% than that of the laser cladding sample, and the surface roughness was reduced by 43.16%. Originality/value The authors believe that the hybrid process proposed in this paper can significantly expand the potential application of laser cladding deposition by solving its limitations, promoting its efficiency and applicability in practical cases.

Hot Forming Springback and Control of 22MnB5 Boron and Magnesium Alloy Sheet

2012 ◽  
Vol 499 ◽  
pp. 96-101 ◽  
Author(s):  
You Dan Guo
Keyword(s):  
Magnesium Alloy ◽  
Cooling Rate ◽  
Sheet Material ◽  
Alloy Sheet ◽  
Magnesium Alloy Sheet ◽  
Thermal Forming ◽  
Material Thickness ◽  
Phase Deformation ◽  
Material Forming ◽  
The Impact

Starting with 22MnB5 boron and magnesium alloy sheet material forming temperature, cooling rate and phase deformation, the impact of cooling rate and temperature change on rebound during hot-stamping as well as the impact of factors such as sheet material thickness on high strength sheet material forming performance. The study shows that the initial conditions, temperature changes during thermal forming and phase deformation are the main factors affecting rebound. When the cooling rate is above the critical cooling rate, rebound increases dramatically. The sheet material thickness has important impact on rebound control and formulating parameters for thermal forming process.

A Computer Simulation Model for Thermal Forming of Ship and Offshore Structures

2018 ◽  
Vol 34 (4) ◽  
pp. 279-309 ◽  
Author(s):  
Kurian Thomas ◽  
Rajiv Sharma ◽  
Subroto Kumar Bhattacharyya
Keyword(s):  
Computer Simulation ◽  
Simulation Model ◽  
Offshore Structures ◽  
Computer Simulation Model ◽  
Thermal Forming

Polyimide Foams for Aerospace Vehicles

2000 ◽  
Vol 12 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Erik S Weiser ◽  
Theodore F Johnson ◽  
Terry L St Clair ◽  
Yoshiaki Echigo ◽  
Hisayasu Kaneshiro ◽  
...  
Keyword(s):  
Next Generation ◽  
Cyclic Testing ◽  
Aerospace Vehicles ◽  
Limiting Oxygen Index ◽  
Excellent Thermal Stability ◽  
Foaming Agents ◽  
Thermal Forming ◽  
Reusable Launch Vehicle ◽  
Wide Range ◽  
Langley Research Center

Due to a demand by the aerospace industry, NASA has begun developing the next generation of polyimide foams which could be utilized to reduce vehicle weight for the X-33 and Reusable Launch Vehicle (RLV) programmes. The activity at NASA Langley Research Center focuses on developing polyimide foam and foam structures which are made using monomeric solutions or salt solutions formed from the reaction of a dianhydride and diamine dissolved in a mixture of foaming agents and alkyl alcohols. This process can produce polyimide foams with varying properties from a large number of monomers and monomer blends. The specific densities of these foams can range from 0.008 g cc−1 to 0.32 g cc−1. Polyimide foams at densities of 0.032 g cc−1 and 0.08 g cc−1 were tested for a wide range of physical properties. The foams demonstrated excellent thermal stability at 321°C, a good thermal conductivity at 25°C of 0.03 W m−1 K−1, compressive strengths as high as 0.84 MPa at 10% deflection and a limiting oxygen index of 51%. Thermomechanical cyclic testing was also performed on these materials for 50 cycles at temperatures from −253°C to 204°C. The foams survived the cyclic testing without debonding or cracking. Thermal forming of the 0.032 g cc−1 foam was performed and a minimum radius curvature of 0.0711 m was achieved. The foams exhibited excellent properties overall and are shown to be viable for use as cryogenic insulation on the next generation RLV.

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