scholarly journals Investigation of the nature of defects on the outer surface of heat-treated seamless pipes

2020 ◽  
pp. 90-93
Author(s):  
O. V. Rozhkova
Keyword(s):  
Heat Treatment ◽  
Outer Surface ◽  
Structural Heterogeneity ◽  
Internal Stresses ◽  
Thermal Cracks ◽  
Defect Zone ◽  
Heat Treated ◽  
Quality Product ◽  
Structural Stresses ◽  
The Difference

Compliance with the quenching technology ensures a high-quality product with the required properties. Violation of the modes of heating for quenching and cooling during quenching leads to the formation of defects such as soft spots and quenching cracks. The presence of soft spots in the metal is unacceptable due to structural stresses and the difference in mechanical properties between the base metal and the defective areas. To remove soft spots, repeated heat treatment is required. Quenching cracks occur due to internal stresses that exceed the resistance to destruction, due to non-simultaneous transformations and thermal expansion and compression. Products with quenching cracks are the final rejects.The article examines soft spots and thermal cracks on the outer surface of seamless pipes formed during heat treatment. The results of metallographic studies of the microstructure in the defect zone are presented, and the genetic and morphological features of defects are determined and studied. The structural heterogeneity was confirmed by Rockwell hardness measurements. Based on the data obtained, the causes of defects were determined.

scholarly journals The Effect of Co-Deposition of SiC Sub-Micron Particles and Heat Treatment on Wear Behaviour of Ni–P Coatings

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 180
Author(s):  
Donya Ahmadkhaniha ◽  
Lucia Lattanzi ◽  
Fabio Bonora ◽  
Annalisa Fortini ◽  
Mattia Merlin ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Friction Coefficient ◽  
Wear Mechanisms ◽  
Composite Coatings ◽  
Wear Behaviour ◽  
Maximum Hardness ◽  
Sic Particles ◽  
Heat Treated ◽  
The Coefficient Of Friction ◽  
The Difference

The purpose of the study is to assess the influence of SiC particles and heat treatment on the wear behaviour of Ni–P coatings when in contact with a 100Cr6 steel. Addition of reinforcing particles and heat treatment are two common methods to increase Ni–P hardness. Ball-on-disc wear tests coupled with SEM investigations were used to compare as-plated and heat-treated coatings, both pure and composite ones, and to evaluate the wear mechanisms. In the as-plated coatings, the presence of SiC particles determined higher friction coefficient and wear rate than the pure Ni–P coatings, despite the limited increase in hardness, of about 15%. The effect of SiC particles was shown in combination with heat treatment. The maximum hardness in pure Ni–P coating was achieved by heating at 400 °C for 1 h while for composite coatings heating for 2 h at 360 °C was sufficient to obtain the maximum hardness. The difference between the friction coefficient of composite and pure coatings was disclosed by heating at 300 °C for 2 h. In other cases, the coefficient of friction (COF) stabilised at similar values. The wear mechanisms involved were mainly abrasion and tribo-oxidation, with the formation of lubricant Fe oxides produced at the counterpart.

Characterization of Microstructure and Mechanical Properties of 6060 Aluminum Alloy Processed by ECAP

2018 ◽  
Vol 275 ◽  
pp. 81-88
Author(s):  
Monika Karoń ◽  
Marcin Adamiak
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Internal Stresses ◽  
Refined Grains ◽  
Angular Pressing ◽  
Heat Treated ◽  
Evolution Of Microstructure

The purpose of this paper is to present the microstructure and mechanical behavior of 6060 aluminum alloy after intense plastic deformation. Equal Channel Angular Pressing (ECAP) was used as a method of severe plastic deformation. Before ECAP part of the samples were heat treated to remove internal stresses in the commercially available aluminium alloy. The evolution of microstructure and tensile strength were tested after 1, 3, 6 and 9 ECAP passes in annealed and non annealed states. It was found that intensely plastically deformed refined grains were present in the tested samples and exhibited increased mechanical properties. Differences were noted between samples without and after heat treatment

Effect of heat treatment on bonding performance of poplar via an insight into dynamic wettability and surface strength transition from outer to inner layers

Holzforschung ◽  
2020 ◽  
Vol 74 (8) ◽  
pp. 777-787 ◽  
Author(s):  
Demiao Chu ◽  
Jun Mu ◽  
Stavros Avramidis ◽  
Sohrab Rahimi ◽  
Zongyuan Lai ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Surface Layer ◽  
Outer Surface ◽  
Near Infrared ◽  
Sessile Drop ◽  
Treated Wood ◽  
Tangential Section ◽  
Surface Strength ◽  
Heat Treated ◽  
Bonding Failure

AbstractHeat treatment (HT) is thought to degrade wood surface wettability and cause gluing problems; this study focused on wettability and surface strength of the surface layer on heat-treated wood. The outer and inner surfaces formed by removing the 1-, 2- and 3-mm surface layers of heat-treated poplar on the tangential section were investigated. Dynamic wetting was analyzed according to the sessile drop method. The bonding failure models on different surfaces were also discussed based on both images of macro- and microscopic fracture interfaces. Using Fourier-transform near-infrared spectroscopy (FT-NIR), the cell wall chemistry on both outer and inner surfaces were analyzed. The results showed that the bonding strength of the outer surface was mainly affected by wettability, whereas the surface strength became the key factor for the inner layers. The removal of the first 1 mm of the surface layer enhanced the wetting process and transferred the failure mode from the glue line to the wood itself. FT-NIR revealed that the intensity of the thermal degradation on inner layers was alleviated with the removal depth; wettability and surface strength were enhanced compared with the outer surface. Surface abrasion and hardness declined, decreasing the surface strength and bonding capacity. This study indicates that the bonding of heat-treated wood is truly affected by the surface strength of the inner layers, in addition to the wettability on the outer surface.

Characterization of Microstructure and Mechanical Properties of AA2219-O and T6 Friction Stir Welds

2019 ◽  
Vol 969 ◽  
pp. 205-210 ◽  
Author(s):  
D. Venkateswarlu ◽  
Muralimohan Cheepu ◽  
P. Nageswara Rao ◽  
S. Senthil Kumaran ◽  
Narayanan Srinivasan
Keyword(s):  
Heat Treatment ◽  
Welding Process ◽  
High Strength ◽  
Friction Stir ◽  
Microhardness Distribution ◽  
Treatment Conditions ◽  
Heat Treated ◽  
The Difference ◽  
Aluminum Alloy 2219 ◽  
Failure Location

In the present study, aluminum alloy 2219 of two different heat treatment states were selected and welded using the friction stir welding process to evaluate the effect substrate on the joint properties. The microstructural observations have exhibited the difference in their characteristics between two heat treatment conditions of 2219-O and T6 conditions. The tensile strength of the AA2219-T6 joints much higher than the AA2219-O joints. Consequently, the microhardness distribution across the different zones varying with two different heat treated conditions. The failure locations and fracture surface features are revealed the significant differences among these two heat treated conditions with the change in their failure location and the fracture morphologies. The optimal welding conditions were analyzed to determine the high strength of the welds with excellent metallurgical properties of the welds.

scholarly journals INFLUENCE OF CARBON CONTENT ON FATIGUE STRENGTH OF DRAWN STEEL TUBES FOR SMALL ONCE-THROUGH BOILER

2012 ◽  
Vol 06 ◽  
pp. 361-366
Author(s):  
DAISUKE YONEKURA ◽  
YUTA FUJIE ◽  
RI-ICHI MURAKAMI ◽  
YUKIHIRO TOKUNAGA
Keyword(s):  
Heat Treatment ◽  
Fatigue Strength ◽  
Carbon Content ◽  
Steel Tube ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Post Heat Treatment ◽  
Steel Tubes ◽  
Heat Treated ◽  
The Difference

Tension-tension fatigue tests were performed to examine the influence of carbon content on the fatigue properties of drawn specific steel tube (STB340) with/without post heat treatment for small once-through boiler. Two different carbon content steel tubes, C =0.06 and 0.12% were prepared. The as-received, as-drawn and post drawing heat treated series for each carbon content tube were prepared for fatigue test. The hardness, grain size and residual stress were measured for each series. As a result, the fatigue strength of as-received and as-drawn series showed a small difference between C =0.06 and 0.12% specimens. However, the post drawing heat treatment series showed obvious difference in the fatigue strength. The fatigue strength of higher carbon content tubes significantly decreased by the post drawing heat treatment, whereas the decrease of fatigue strength was little for lower carbon content heat treated tubes. The difference of fatigue strength was mainly caused by the degree of relaxation of work hardening by post heat treatment.

Producing a Random Recrystallization Texture in 6111 Aluminium Alloy

2005 ◽  
Vol 495-497 ◽  
pp. 591-596 ◽  
Author(s):  
Cynthia S.T. Chang ◽  
A.S.C. Yeung ◽  
B.J. Duggan
Keyword(s):  
Heat Treatment ◽  
Aluminium Alloy ◽  
Solution Heat Treatment ◽  
Recrystallization Texture ◽  
Rolling Texture ◽  
Heat Treated ◽  
Complete Recrystallization ◽  
Hot Band ◽  
Cold Rolled ◽  
The Difference

6111 Aluminium Alloy in the hot band state was cold rolled to 80% was then annealed at 450oC, 500oC and 540oC for recrystallization. The hot band was also solution heat treated, cold rolled and annealed to the same temperature to look at the difference in the recrystallization texture and precipitation states. It was found that the samples which were cold rolled and annealed without solution heat treatment gave Goss and P components after annealing. For the samples with solution heat treatment, the 450oC sample has a retained Cu type rolling texture while for the 500oC and 540oC the textures are quite random. The retained rolling texture found in the 450oC sample is due to the fact that it was partially recrystallized as the precipitates prevent complete recrystallization. The difference in the precipitation states during and after annealing of the samples with and without solution heat treatment affects the final recrystallization texture.

Effect of heat treatment on the magnetic behaviour of powder steel 50Ni2Mo under uni-axial tension

2011 ◽  
Vol 226 (6) ◽  
pp. 1462-1471 ◽  
Author(s):  
E S Gorkunov ◽  
Y V Subachev ◽  
S M Zadvorkin ◽  
A I Ulyanov ◽  
L S Goruleva
Keyword(s):  
Heat Treatment ◽  
Coercive Force ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Powder Steel ◽  
Magnetic Behaviour ◽  
Magnetic Characteristics ◽  
Internal Stresses ◽  
Treatment Conditions ◽  
Heat Treated

In this study, investigation results on the effect of heat treatment conditions on the mechanical properties, internal stresses, magnetic characteristics, and electrical resistivity of powder steel 50Ni2Mo are presented. Coercive force and maximum magnetization are shown to be applicable as magnetic test parameters to reveal underheating for quenching. Heating for quenching above the critical point [Formula: see text] up to 910°С has an insignificant effect on the mechanical characteristics of the steel tested. It has been demonstrated that the use of the coercive force measured on minor magnetic hysteresis loops is preferable when estimating the level of applied tensile stresses in heat-treated powder steel 50Ni2Mo.

Study of the properties for stabilized polyacrylonitrile thermally treated in air

2021 ◽  
Vol 87 (7) ◽  
pp. 30-37
Author(s):  
V. V. Kozlov ◽  
A. A. Vasilev ◽  
I. G. Gorichev ◽  
A. Т. Kalashnik ◽  
V. G. Kostishin ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Carbon Materials ◽  
Initial Structure ◽  
Preliminary Treatment ◽  
X Ray Diffraction ◽  
Exponential Factor ◽  
X Ray ◽  
Diffusion Limitations ◽  
Heat Treated ◽  
The Difference

Developing of nanotechnology-based electronics entails developing of new carbon nanocrystalline materials with predetermined physicochemical properties, e.g., obtained by synthesis of polyacrylonitrile (PAN) in conditions of heat treatment. We have studied the properties of PAN heat-treated in air in the temperature range 150 – 250°C and the effect of stabilization on the kinetic parameters of synthesis and thermochemical properties of carbon material upon heat treatment in N2 atmosphere. It is shown that an increase in the temperature of a preliminary treatment up to 200°C leads to a decrease in the activation energy and pre-exponential factor compared to the corresponding values characteristic for the initial polymer (from 90.9 and 3.1 × 106 to 53.3 kJ/mol and 1.1 × 103 min–1, respectively), which indicates to the occurrence of diffusion limitations. When the temperature of a preliminary treatment in air increases from 180 to 250°C, the difference between temperature peaks for DSC and TGA curves decreases due to appearance of a «core-shell» structure. XRD data indicate that the initial PAN structure does not change up to 150°C. Further increase in the temperature leads to significant changes in the initial structure of the polymer which are manifested in a decrease in the peak area in the X-ray diffraction pattern of the polymer. The results obtained can be used in the development of a method for the synthesis of carbon materials with controlled properties predetermined at the stage of stabilization.

Density Assessment of Heat Treated Malaysian Hardwood Timber: The Case of Kapur (Dryobalanops spp.) and Keruing (Dipterocarpus spp.)

2015 ◽  
Vol 802 ◽  
pp. 107-111
Author(s):  
Nur Ilya Farhana Md Noh ◽  
Zakiah Ahmad ◽  
Mohd Hisbany Mohd Hashim
Keyword(s):  
Heat Treatment ◽  
Treatment Process ◽  
Treatment Method ◽  
Heat Treatment Process ◽  
Environmental Friendly ◽  
Heat Treated ◽  
Movement Stability ◽  
Chemical Preservatives ◽  
The Difference ◽  
Density Assessment

Heat treatment is one of the environmental friendly ways to treat timber that will lead to the improvement of timber natural quality and equip the timber with new properties. It is an eco friendly and alternative treatment method that will modify the properties of timber by using high temperature instead of using chemical preservatives as common practice. This paper presents the effect of heat treatment on physical properties which is density for two types of Malaysia hardwood namelykapurandkeruing. Specially design electronic furnace was used as an oven for the heat treatment process. The result shows a reduction in density after heat treatment, however the difference is not merely significant. Lower in density indicates a weight loss which theoretically caused by moisture content loss thus leading to the increment of movement stability.

Effect of a Complex Heat Treatment on the Structure of 300M Steel

1981 ◽  
Vol 39 ◽  
pp. 312-313
Author(s):  
R. Padmanabhan ◽  
W. E. Wood
Keyword(s):  
Heat Treatment ◽  
Metal Carbides ◽  
Austenite Grain Size ◽  
300M Steel ◽  
Heat Treated ◽  
Strain Fracture ◽  
Prior Austenite Grain Size ◽  
Short Time ◽  
Final Tempering ◽  
Similar Yield

Intermediate high temperature tempering prior to subsequent reaustenitization has been shown to double the plane strain fracture toughness as compared to conventionally heat treated UHSLA steels, at similar yield strength levels. The precipitation (during tempering) of metal carbides and their subsequent partial redissolution and refinement (during reaustenitization), in addition to the reduction in the prior austenite grain size during the cycling operation have all been suggested to contribute to the observed improvement in the mechanical properties. In this investigation, 300M steel was initially austenitized at 1143°K and then subjected to intermediate tempering at 923°K for 1 hr. before reaustenitizing at 1123°K for a short time and final tempering at 583°K. The changes in the microstructure responsible for the improvement in the properties have been studied and compared with conventionally heat treated steel. Fig. 1 shows interlath films of retained austenite produced during conventionally heat treatment.

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