THE EFFECT OF LOW TEMPERATURES UPON THE IMPACT RESISTANCE OF STEEL CASTINGS

1930 ◽  
Vol 2 (5) ◽  
pp. 327-340
Author(s):  
R. W. Moffatt
Keyword(s):  
Heat Treatment ◽  
Low Temperatures ◽  
Room Temperature ◽  
Freezing Point ◽  
High Carbon Steel ◽  
Impact Resistance ◽  
Nickel Steel ◽  
Heat Treated ◽  
Steel Castings ◽  
The Impact

The investigation deals with the effect of low temperatures on the impact resistance of steel castings and forgings. Low, medium and high carbon steel castings and a few alloys of vanadium, nickel, and vanadium-nickel steel castings were examined. The metals were subjected to low temperatures, both before and after heat treatment. The temperatures for the tests varied from room temperatures to temperatures well below 0° F., so as to extend below the ordinary atmospheric range of temperatures found in northern climates.It was found that the impact resistances of the metals decreased for temperatures below the freezing point. For specimens, not heat treated, the impact resistance at − 40° F. may be only one-third to one-half of that at room temperature. Heat treatment increases the impact resistance at room temperatures and temperatures below the freezing point. The impact resistance at − 40° F. for the heat-treated metal compared favorably with the impact resistance of the untreated metal at room temperature, 68° F. Heat treatment may slightly lower the yield point and the ultimate tensile strength, but it increases the ductility and the impact resistance of the metal. By proper heat treatment of steel castings the impact resistance at − 40° F. may be brought over 300% higher than that of the untreated metal at that temperature.

The influence of process parameters on the impact resistance of 3D printed PLA specimens under water-absorption and heat-treated conditions

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Pradeep Kumar Mishra ◽  
Senthil Ponnusamy ◽  
Mohan Satyanarayana Reddy Nallamilli
Keyword(s):  
Heat Treatment ◽  
Impact Strength ◽  
Water Absorption ◽  
Process Parameters ◽  
Impact Resistance ◽  
Post Processing ◽  
Content Type ◽  
Heat Treated ◽  
3D Printed ◽  
The Impact

Purpose The purpose of this paper is to analyse the effect of water absorption and heat treatment on the impact strength of three-dimensional (3D) printed Izod specimens. A low-cost post-processing technique is proposed to improve the impact strength of 3D printed parts substantially. Design/methodology/approach In the present work, the effect of water absorption and the heat-treatment on the impact resistance of 3D printed poly-lactic acid parts possessing different layer-height, build-orientation and raster-orientation was studied. Water absorption tests were conducted in distilled water and it was observed that the water- absorption in specimens follows the Fickian diffusion mechanism. A set of specimens was heat-treated at 120°C for 1 h using an induction furnace. Post water absorption and heat-treatment a significant increase in the impact resistance is noticed and especially a steep increase in impact resistance is observed in heat-treated specimens. Findings Experimental findings show that raster orientation played a major role in the impact resistance of a 3D printed structure in comparison to other process parameters. The order of influence of process parameters on the impact strength of specimens was disclosed by the mean effect plots. In terms of processing time and cost, the post-processing heat-treatment approach was found to be convenient compared to the water absorption technique. Originality/value This paper presents a new set of low-cost post-processing techniques (water-absorption and heat-treatment) for improving the impact strength of 3D printed specimens.

scholarly journals Impact of Heat Treatment on the Freezing Points of Cow and Goat Milk

2009 ◽  
Vol 78 (4) ◽  
pp. 679-684
Author(s):  
Bohumíra Janštová ◽  
Pavlína Navrátilová ◽  
Michaela Dračková ◽  
Hana Přidalová ◽  
Lenka Vorlová
Keyword(s):  
Heat Treatment ◽  
Freezing Point ◽  
Goat Milk ◽  
Treatment Temperature ◽  
Raw Material ◽  
Cow Milk ◽  
Heat Treated ◽  
Bulk Tank ◽  
The Individual ◽  
The Impact

The aim of this study was to monitor the impact of heat treatment variables on the freezing point of cow and goat milk. The freezing point (FP) was established in 30 bulk tank samples of goat milk and in 30 bulk tank samples of cow milk which were subject to laboratory heat treatment at temperatures of 72 °C (A), 85 °C (B), 95 °C (C), with the same exposition times of 20 s. Freezing point measurements of raw and heat-treated milk were carried out in compliance with the Standard CTS 57 0538 by a thermistor cryoscope. The FP of raw cow milk increased with heat treatment from the initial values of -0.5252 ± 0.0114 °C (O) by 0.0023 °C (A), 0.0034 °C (B) and 0.0051°C (C). Changes in FP values of goat milk were detected, from its initial value of –0.5530 ± 0.0086 °C there was an increase in the FP depending on the mode of heat treatment due to pasteurization by an average of 0.0028 °C (A), 0.0036 °C (B) and 0.0054 °C (C). The dynamics of the changes were similar both in goat and cow milk. Freezing point values in cow and goat milk differed (P ⪬ 0.01) when compared to the freezing point of untreated milk after the individual interventions as well as when compared between each other. An increase in the heat treatment temperature of cow and goat milk causes an increase in the freezing point (a shift towards zero). These results can be used in practice for checking the raw material in dairy industry.

scholarly journals The effect of heat treatment and impact angle on the erosion behavior of nickel-tungsten carbide cold spray coating using response surface methodology

2021 ◽  
Author(s):  
Marios Kazasidis ◽  
Elisa Verna ◽  
Shuo Yin ◽  
Rocco Lupoi
Keyword(s):  
Heat Treatment ◽  
Response Surface Methodology ◽  
Mass Loss ◽  
Tungsten Carbide ◽  
Response Surface ◽  
Spray Coating ◽  
Impact Angle ◽  
Control Factors ◽  
Heat Treated ◽  
The Impact

AbstractThis study elucidates the performance of cold-sprayed tungsten carbide-nickel coating against solid particle impingement erosion using alumina (corundum) particles. After the coating fabrication, part of the specimens followed two different annealing heat treatment cycles with peak temperatures of 600 °C and 800 °C. The coatings were examined in terms of microstructure in the as-sprayed (AS) and the two heat-treated conditions (HT1, HT2). Subsequently, the erosion tests were carried out using design of experiments with two control factors and two replicate measurements in each case. The effect of the heat treatment on the mass loss of the coatings was investigated at the three levels (AS, HT1, HT2), as well as the impact angle of the erodents (30°, 60°, 90°). Finally, the response surface methodology (RSM) was applied to analyze and optimize the results, building the mathematical models that relate the significant variables and their interactions to the output response (mass loss) for each coating condition. The obtained results demonstrated that erosion minimization was achieved when the coating was heat treated at 600 °C and the angle was 90°.

Effect of Cooling Rate on Microstructure and Properties of Heat-Treated Fe3Al Intermetallics

2011 ◽  
Vol 189-193 ◽  
pp. 3891-3894
Author(s):  
Ya Min Li ◽  
Hong Jun Liu ◽  
Yuan Hao
Keyword(s):  
Heat Treatment ◽  
Cooling Rate ◽  
Lattice Distortion ◽  
Annealing Furnace ◽  
Microstructure And Properties ◽  
Homogenizing Annealing ◽  
Heat Treated ◽  
Mixed Fracture ◽  
Sand Mould ◽  
The Impact

The casting Fe3Al intermetallics were solidified in sodium silicate sand mould and permanent mould respectively to get different cooling rates. After heat treatment (1000°С/15 h homogenizing annealing + furnace cooling followed by 600°С/1 h tempering + oil quenching), the microstructure and properties of Fe3Al intermetallics were investigated. The results show that the heat-treated Fe3Al intermetallics at higher cooling rate has finer grained microstructure than lower cooling rate, and the lattice distortion increases due to the higher solid solubility of the elements Cr and B at higher cooling rate. The tensile strength and hardness of the Fe3Al intermetallics at higher cooling rate are slightly higher also. However, the impact power of intermetallics at higher cooling rate is 67.5% higher than that at lower cooling rate, and the impact fracture mode is also transformed from intercrystalline fracture at lower cooling rate to intercrystallin+transcrystalline mixed fracture at higher cooling rate.

Application of Tailored Heat Treated Blanks under Quasi Series Conditions

2007 ◽  
Vol 344 ◽  
pp. 383-390 ◽  
Author(s):  
Marion Merklein ◽  
Uwe Vogt
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Local Heat ◽  
Strength Distribution ◽  
Process Window ◽  
Short Term ◽  
Forming Process ◽  
Heat Treated ◽  
Set Up ◽  
The Impact

Tailored Heat Treated Blanks (THTB) are blanks that exhibit locally different strength specifically optimized for the succeeding forming process. The strength distribution is set by a local, short-term heat treatment modifying the mechanical properties of the material. Hence, THTB allow enhancing forming limits significantly leading to shorter and more robust manufacture process chains. In order to qualify the use of THTB under quasi series conditions, the interdependencies of the blank’s local heat treatment and the entire process chain of the car body manufacture have to be analyzed. In this respect, the impact of a short-term heat treatment on the mechanical properties of AA6181PX, a commonly used aluminum alloy in today’s car bodies, was studied. Also the influence of a short-term heat treatment on the coil lubricant, usually already applied by the material supplier, was given a closer look. Based on these experiments process restrictions for the application of THTB in an industrial automotive environment were derived and a process window for the THTB design was set up. In conclusion, strategies were defined how to enhance the found process boundaries leading to a more robust process window.

scholarly journals Characteristics of Black Ginseng (Panax ginseng C.A. Mayer) Production Using Ginseng Stored at Low Temperature after Harvest

Metabolites ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 98
Author(s):  
Hyo Bin Oh ◽  
Ji Won Lee ◽  
Da Eun Lee ◽  
Soo Chang Na ◽  
Da Eun Jeong ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Low Temperature ◽  
Panax Ginseng ◽  
Low Temperatures ◽  
Sugar Content ◽  
Base Material ◽  
Free Sugar ◽  
Drying Process ◽  
Heat Treated ◽  
Black Ginseng

Ginseng processing often involves multiple drying and heat treatments. Ginseng is typically processed within one week of harvesting or is stored at low temperatures to prevent spoilage. Black ginseng (BG) is manufactured by repeating the heat treatment and drying process of ginseng several times. We compared the suitability of low-temperature stored ginseng (SG) and harvested ginseng (HG) as the components for black ginseng production. SG and HG were processed into black ginseng and the appearance change, free sugar content, and benzo[a]pyrene (BAP) content were observed. Appearance observations showed the SG to be suitable in terms of quality when heat-treated at a temperature of 95 ℃ or higher. The BAP content of the SG increased significantly as the steaming process was repeated. A maximum BAP concentration of 5.31 ± 1.12 μg/kg was measured in SG steamed from 2 to 5 times, making it unsuitable for processing into BG. SG and HG showed similar trends in the content of sucrose, fructose, and glucose during steaming. This study aimed to facilitate the proper choice of base material to improve the safety of black ginseng by limiting BAP production during processing.

Comparison of Microstructure and Mechanical Properties of Additively Manufactured and Conventional Maraging Steel

2020 ◽  
Vol 405 ◽  
pp. 133-138
Author(s):  
Ludmila Kučerová ◽  
Andrea Jandová ◽  
Ivana Zetková
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Maraging Steel ◽  
Precipitation Hardening ◽  
High Strength ◽  
Hardness Measurement ◽  
Nickel Steel ◽  
Heat Treated ◽  
Good Material ◽  
Iron Nickel

Maraging steel is an iron-nickel steel alloy, which achieves very good material properties like high toughness, hardness, good weldability, high strength and dimensional stability during heat treatment. In this work, maraging steel 18Ni-300 was manufactured by selective laser melting. It is a method of additive manufacturing (AM) technology, which produces prototypes and functional parts. Sample of additively manufactured and conventional steel with the same chemical composition were tested after in three different states – heat treated (as-built/as-received), solution annealed and precipitation hardened. Resulting microstructures were analysed by light and scanning electron microscopy and mechanical properties were obtained by hardness measurement and tensile test. Cellular martensitic microstructures were observed in additively manufactured samples and conventional maraging steel consisted of lath martensitic microstructures. Very similar mechanical properties were obtained for both steels after the application of the same heat treatment. Ultimate tensile strengths reached 839 – 900 MPa for samples without heat treatment and heat treated by solution annealing, the samples after precipitation hardening had tensile strengths of 1577 – 1711 MPa.

Variations in Fracture Toughness for Alloy 718 Given a Modified Heat Treatment

1990 ◽  
Vol 112 (1) ◽  
pp. 116-123 ◽  
Author(s):  
W. J. Mills ◽  
L. D. Blackburn
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
Fracture Mechanisms ◽  
Alloy 718 ◽  
Percent Confidence Level ◽  
Heat Treated ◽  
Curve Method ◽  
Heat Treated Condition ◽  
The Impact ◽  
Product Forms

Heat-to-heat and product-form variations in the JIC fracture toughness for Alloy 718 were characterized at 24, 427, and 538°C using the multiple-specimen JR-curve method. Six different material heats along with three product forms from one of the heats were tested in the modified heat treated condition. This heat treatment was developed at Idaho National Engineering Laboratory to improve the impact toughness for Alloy 718 weldments, but it has also been found to enhance the fracture resistance for the base metal. Statistical analysis of test results revealed four distinguishable JIC levels with mean toughness levels ranging from 87 to 190 kJ/m2 at 24°C. At 538°C, JIC values were 15 to 20 percent lower than room temperature toughness levels. Minimum expected values of JIC (ranging from 72 kJ/m2 at 24°C to 48 kJ/m2 at 538°C) and dJR/da (27 MPa at 24 to 538°C) were established based on tolerance intervals bracketing 90 percent of the lowest JIC and dJR/da populations at a 95 percent confidence level. Metallographic and fractographic examinations were performed to relate key microstructural features and operative fracture mechanisms to macroscopic properties.

Effect of Alkali Treatment and Molding Temperature on Flexural and Impact Properties of Coir-Fibre-Epoxy Composite

2015 ◽  
Vol 24 (4) ◽  
pp. 096369351502400
Author(s):  
C. K. Tai ◽  
R. Ahmad ◽  
H. M. Akil ◽  
M. M. Ratnam
Keyword(s):  
Room Temperature ◽  
Alkali Treatment ◽  
Flexural Modulus ◽  
Impact Resistance ◽  
Compression Molding ◽  
Impact Properties ◽  
Molding Temperature ◽  
Coir Fibre ◽  
Fibre Composites ◽  
The Impact

The combined effects of alkali treatment and compression molding temperature on the flexural strength and impact resistance of woven coir fibre composites are investigated. Ten pieces of composites plates made from single-layer woven coir fibre fabricated under different process parameters were used in the study. Five pieces of the coir woven fibre were treated with 6% sodium hydroxide (NaOH) solution while another five were left untreated. The compression molding temperature were varied between room temperature (25°C), 50°C, 75°C, 100°C and 125°C. The flexural properties of the composite were evaluated using the three-point flexural test, while the impact resistance was investigated by drop weight impact tests using a specially designed indenter. The indentation radius on each test specimen was measured using a 3-D metrology system and the depth of indentation was determined from the geometry of the indenter. The results show that the maximum flexural load to failure is improved by 38.9% when the fibres were treated and the compression molding temperature is increased to 125°C. The flexural modulus generally decreased with increase in the molding temperature. The depth of indentation in the treated coir woven composites is lower than that of untreated fibre composite at all molding temperatures. The impact resistance of both untreated and treated fibre composites decreased with the increase in the compression molding temperature. Composites fabricated by molding at room temperature, 50°C and 75°C using treated fibre produced the best impact properties.

scholarly journals Wood Surface Changes of Heat-Treated Cunninghamia lanceolate Following Natural Weathering

Forests ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 791
Author(s):  
Xinjie Cui ◽  
Junji Matsumura
Keyword(s):  
Heat Treatment ◽  
Wood Surface ◽  
Color Change ◽  
Thermal Modification ◽  
Protective Measure ◽  
Surface Color ◽  
Natural Exposure ◽  
Heat Treated ◽  
The Impact ◽  
Cunninghamia Lanceolate

To quickly clarify the effect of heat treatment on weatherability of Cunninghamia lanceolate (Lamb.) Hook., we investigated the surface degradation under natural exposure. A comparison between heat-treated and untreated samples was taken based on surface color changes and structural decay at each interval. Over four weeks of natural exposure, multiple measurements were carried out. Results show that color change decreased in the order of 220 °C heat-treated > untreated > 190 °C heat-treated. The results also indicate that the wood surface color stability was improved via the proper temperature of thermal modification. Low vacuum scanning electron microscopy (LVSEM) results expressed that thermal modification itself had caused shrinking in the wood surface structure. From the beginning of the weathering process, the heat treatment affected the surface structural stability. After natural exposure, the degree of wood structure decay followed the pattern 220 °C heat-treated > 190 °C heat-treated > untreated. Therefore, when considering the impact on the structure, thermal modification treatment as a protective measure to prevent weathering was not an ideal approach and requires further improvement.

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