scholarly journals Increasing the construction strength of petroleum pipes operating in agressive environment

2021 ◽  
pp. 70-76
Author(s):  
V.S. Chmeliova ◽  
H.I. Perchun
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Hydrogen Sulfide ◽  
Brittle Fracture ◽  
High Resistance ◽  
Structural Strength ◽  
Aggressive Environment ◽  
The Impact ◽  
Resistance To Brittle Fracture ◽  
Hydrogen Sulfide Cracking

Purpose. Questions about ways to increase the structural strength of oil country tubular goods are considered. Alloying and heat treatment of medium-alloy steels should ensure: pro-carbonization to the structure of martensite and lower bainite with a minimum carbon content (C ≤ 0.3 %), high resistance to brittle fracture and hydrogen embrittlement, the formation of uniformly distributed finely dispersed carbides and sulphides of a round shape to reduce diffusion mobile hydrogen is absorbed by steel. Propose modes of thermal treatment of casing pipes that provide the required level of mechanical and operational properties. Methodology. We used standard techniques for determining the mechanical properties in tension, dynamic bending tests and fracture studies. Results. The modes of heat treatment of casing pipes of strength category E, L are proposed, which provide the required level of mechanical and operational properties and an increase in structural strength. Originality. A systematic analysis of the influence of various factors on the structural strength of oil country tubular goods operating in an aggressive environment has been carried out. The highest degree of correlation between the value of the impact toughness and the tough component in the fracture is shown. Cooling of pipes with a nozzle sprayer of the design of the Department of Heat Treatment of Metals of NMetAU, which provides high resistance to brittle fracture by increasing the proportion of the viscous component and changing the microrelief of the cup fracture. Practical value. The proposed technology of heat treatment of oil pipes, working in an aggressive environment, provides the required level of mechanical properties and resistance to hydrogen sulfide cracking. Keywords: structural strength; oil country tubular goods; alloying; heat treatment; strength categories;temperature and deformation parameters; hydrogen sulfide cracking; brittle fracture resistance

On the Methods for Assessing the Resistance of Steels to Brittle Fracture

2021 ◽  
pp. 59-64
Author(s):  
A.P. Korchagin ◽  
◽  
K.A. Kuznetsov ◽  
A.M. Kuznetsov ◽  
S.I. Kirillov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Brittle Fracture ◽  
Impact Strength ◽  
Low Temperatures ◽  
Physical And Mechanical Properties ◽  
Correct Choice ◽  
Temperature Dependences ◽  
And Control ◽  
The Impact ◽  
Resistance To Brittle Fracture

The problem of assessing steels durability, their resistance to brittle fracture in the structures used in various branches of industry, remains relevant at the development of the new equipment and control of the old equipment. Standard strength calculations do not give a complete picture of the ability of steels due to their physical and mechanical properties to resist the formation and further development of defects and cracks under the action of actual stresses. The correct choice of a structural material for technical devices operating at low temperatures, knowledge of its characteristics of resistance to brittle fracture, understanding of brittle fracture mechanism at low temperatures and research in this area are of great importance. Since 1980s, JSC IrkutskNIIkhimmash systematically conducts the research works related to impact strength characteristics. These works are carried out in connection with the need for assessing the resistance to brittle fracture of metal of the equipment for storing oil products, vessels and pipelines, drill pipes and tubing, etc. As a result of many years of research, the authors accumulated significant experimental material in the form of temperature dependences of impact strength - both for the material of various types of blanks (sheets, pipes, forgings) in the state of delivery, and for the metal of technical devices elements after their operation of various duration. The main objective of the article is to assist specialists in establishing the correct choice of steel for the new or old structures in terms of their resistance to brittle fracture without conducting special studies. Specialists can select the closest steel analogue (on chemical composition, mechanical properties, and the type of product without making cuts from the structure or blanks for additional research), and set the numerical value of the impact strength, critical temperature of brittleness and the stress intensity factor for any temperature in the range from –40 to 20° С in order to use them in further calculations.

The Effect of Aging Heat Treatment on the Microstructure and Mechanical Properties of 10Cr20Ni25Mo1.5NbN Austenitic Steel

2016 ◽  
Vol 35 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Zhiyuan Liang ◽  
Wanhua Sha ◽  
Qinxin Zhao ◽  
Chongbin Wang ◽  
Jianyong Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Heat Treatment ◽  
Austenitic Steel ◽  
Treatment Time ◽  
Aging Treatment ◽  
Secondary Phases ◽  
Aging Heat Treatment ◽  
Microstructure And Mechanical Properties ◽  
The Impact

AbstractThe effect of aging heat treatment on the microstructure and mechanical properties of 10Cr20Ni25Mo1.5NbN austenitic steel was investigated in this article. The microstructure was characterized by scanning electron microscopy, energy dispersive spectrometry and transmission electron microscopy. Results show that the microstructure of 10Cr20Ni25Mo1.5NbN austenitic is composed of austenite. This steel was strengthened by precipitates of secondary phases that were mainly M23C6 carbides and NbCrN nitrides. As aging treatment time increased, the tensile strength first rose (0–3,000 h) and then fell (3,000–5,000 h) due to the decrease of high density of dislocations. The impact absorbed energy decreased sharply, causing the sulfides to precipitate at the grain boundary. Therefore, the content of sulfur should be strictly controlled in the steelmaking process.

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 Layered metal composites with high resistance to brittle fracture at low temperatures

2018 ◽  
Author(s):  
S. V. Gladkovsky ◽  
I. S. Kamantsev ◽  
S. V. Kuteneva ◽  
D. A. Dvoynikov ◽  
A. V. Kuznetsov
Keyword(s):  
Brittle Fracture ◽  
High Resistance ◽  
Low Temperatures ◽  
Metal Composites ◽  
Resistance To Brittle Fracture

Influence of the conditions of casting and heat treatment on the structure and mechanical properties of the AlMg10 alloy

2017 ◽  
Vol 1 (83) ◽  
pp. 26-32
Author(s):  
P. Kordas
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Liquid State ◽  
Precipitation Hardening ◽  
Solidification Rate ◽  
Dendritic Structure ◽  
Grain Structure ◽  
Alloy Castings ◽  
Die Castings ◽  
The Impact

Purpose: Assessment of the possibilities of shaping the structure and improvement of mechanical properties of casting from AlMg10 alloy through a selection of casting technology and precipitation hardening. Design/methodology/approach: the work evaluated the impact of casting and heat treatment technology on the mechanical properties and structure of AlMg10 alloy castings. The tests were performed on 200 mm × 100 mm × 25 mm plate castings produced by gravity casting methods for sand and metal moulds and by a liquid state press moulding technology. Castings made with these technologies solidify in substantially different heat- evaporation conditions and exhibit varying degrees of primary structure fragmentation. Metallographic and strength tests were performed on raw castings and after heat treatment. Findings: The changes in the morphology and size of primary crystals and the dispersion of the reinforcing phase according to the casting solidification rate and the precipitation hardening treatment were analyzed. Solidifying castings in the form of sand show a globular structure, whereas in die and press castings, a typically dendritic structure occurs, with the dendritic crystals in pressed castings being much smaller in size than the die castings. In castings which were not heat-treated, the reinforcing phase of Al3Mg2 occurs in interdendritic spaces, and its dispersion increases with the rate of cooling. After supersaturation and ageing treatments, the phase α has a grain structure in all samples. The largest dispersion of reinforcing molecules is characterized by press castings. In a raw state, the highest mechanical properties are shown by castings made in the form of sand and the method of pressing in a liquid state. Heat treatment of AlMg10 alloy castings significantly influences the increase of mechanical indexes in all castings investigated. The highest features of Rm are approx. 330 MPa and A5 above 10% is obtained in castings made by the press method. Research limitations/implications: Particular attention should be paid to the avoidance of the effects of slag inclusion, shrinkage and magnesium oxidation during casting of AlMg10 alloys. In die castings of a plate type, due to own stresses, a significant decrease in mechanical properties occurs. Practical implications: The most advantageous mechanical properties of AlMg10 alloy castings are obtained by using liquid-state pressing technology. In addition, this technology makes it possible to produce thin-walled castings of high dimensional accuracy, high air- tightness, fine grain structure, lack of surface defects and low roughness. Originality/value: The paper presents the possibility of improving the mechanical properties of AlMg10 castings by applying heat treatment. It has been proven that the casting method has a significant effect on the mechanical properties of the castings.

Effect of Heat Treatment Hardness of Al-Cu-Mg-Li-Zr, Al-Mg-Si and and Al-Mg-Zn Alloys-Experimental Correlation Using Factorial DOE and ANOVA Methods

2014 ◽  
Vol 881-883 ◽  
pp. 1317-1329 ◽  
Author(s):  
Mahmoud M. Tash ◽  
Saleh Alkahtani
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Cold Work ◽  
Solution Treatment ◽  
Statistical Design ◽  
Aging Treatment ◽  
Fractional Factorial ◽  
Statistical Design Of Experiments ◽  
The Impact ◽  
Zn Alloys

The present study was conducted to investigate the effect of heat treatment on the aging and mechanical behavior of Al-Cu-Mg-Li-Zr , Al-Mg-Si and and Al-Mg-Zn alloys (8090 , 6082 and 7075). The effect of cold work after solution treatment, aging parameters (time and temperature) on the microstructure and mechanical properties were studied. Attempts are made to determine the combined effect of cold work and aging treatment on the hardness, UTS and microstructure for these alloys. By study the impact of different heat treatments for Al-Mg-Si alloys (6082), Al-Cu-Mg-Li-Zr (8090) and Al-Mg-Zn (7075) aluminum alloys on the hardness and mechanical properties, it is possible to determine conditions necessary to achieve better mechanical properties and the maximum levels of hardness and values corresponding to those considered suitable for commercial applications of these alloys.Design of Experiment (DOE) method in Minitab is used to measure the impact of various factors and how they relate. Correlation between the hardness and different metallurgical factors for these alloys at both quantitative and qualitative are investigated and analysed. A statistical design of experiments (DOE) approach using fractional factorial design was applied to determine the influence of controlling variables of cold work and heat treatment parameters and any interactions between them on the hardness of the above alloys. A mathematical model is developed to relate the alloy hardness with the different metallurgical parameters to acquire an understanding of the effects of these variables and their interactions on the hardness of wrought Al-alloys. It is noticed that cold work, following solution treatment, accelerates the precipitation rate leading to a rise in strength

The Influence of Boron on Structure and Mechanical Properties of Bainite Ductile Iron in the Step Austempering in Room Temperature Machine Oil

2010 ◽  
Vol 139-141 ◽  
pp. 235-238
Author(s):  
De Qiang Wei
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Cast Iron ◽  
Impact Strength ◽  
Ductile Iron ◽  
Room Temperature ◽  
Solute Drag ◽  
Ductile Cast Iron ◽  
Treatment Technique ◽  
The Impact

In this paper, the low alloy bainite ductile cast iron has been obtained by a new heat treatment technique of the step austempering in room-temperature machine oil. The effects of element boron, manganese and copper on structure and mechanical properties of the bainite ductile cast Iron in above-mentioned process are investigated. The phenomenon, hardness lag of the alloyed bainite ductile cast Iron, has been discussed. It shows that after the step austempering in room-temperature machine oil, the hardness will increases with the time. It is found that boron and manganese can increase the hardness and reduce the impact strength while copper can increase the impact strength. The results show that reasonable alloyed elements can improve mechanical properties of the bainite ductile cast Iron. Essentially, hardness lag of the alloyed bainite ductile cast Iron is resulted from solute drag-like effect.

Investigation of Heat Treatment on Mechanical Properties of SAE4320 and SAE8620 Alloys

2013 ◽  
Vol 834-836 ◽  
pp. 816-819 ◽  
Author(s):  
Li Jun Tan ◽  
Jun Qiao Wang ◽  
Qing Qun Wang ◽  
Xin Long Chen ◽  
Si Zhu Zhou
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Impact Toughness ◽  
Deformation Property ◽  
New Product ◽  
Heat Treatments ◽  
Impact Properties ◽  
The Impact

The tensile and impact properties of SAE4320 and SAE8620 alloys were investigated. Various heat treatments were applied to these two alloys, including different pre-heat treatment. The results shown that after Carburizing and Quenching, both SAE4320 and SAE8620 alloys were highly sensitively to V-notches for their impact samples. In any case, SAE4320 alloy revealed higher tensile strength, better impact toughness and deformation property. Previous work shown that after Carburizing and Quenching, the impact toughness of SAE8620 alloy was too low, the products made of it was very dangerous. Based on the results, a new advanced product was made of SAE4320 alloy instead of SAE8620 alloy. And the new product exhibited good properties. The impact value of the new product far exceeded the older products.

scholarly journals INVESTIGATION OF HOT PLASTIC DEFORMATION OF LABORATORY AXIAL FLOATS

2021 ◽  
pp. 12-16
Author(s):  
Oleksandr Babachenko ◽  
Ganna Kononenko ◽  
Katerina Domina ◽  
Rostislav Podolskyi ◽  
Olena Safronova
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Plastic Deformation ◽  
Chemical Composition ◽  
Physical And Mechanical Properties ◽  
Pressure Treatment ◽  
Initial Length ◽  
Hot Plastic Deformation ◽  
The Impact ◽  
Further Development

A review of research in the field of modeling experiments on heat treatment and pressure treatment of metal and the impact on the physical and mechanical properties of steel with a chemical composition of 0.59% C, 0.31% Si, 0.73% Mn. A mathematical model for calculating the physical and mechanical properties of steel in the process of hot plastic deformation has been developed and prospects for further development of research in this area have been identified. As a result of modeling, the following functions were obtained: the amount of deformation in the direction of the applied force divided by the initial length of the material. The coefficient of elongation of the material with the actual chemical composition at a temperature of 1250 ± 10 ° C, which was 0.32. When comparing the values of the load that was applied to the GPA in the laboratory and the results of calculations using the developed model, it was found that they have close values of about 45 MPa. This confirms the adequacy of the obtained model.A review of research in the field of modeling experiments on heat treatment and pressure treatment of metal and the impact on the physical and mechanical properties of steel with a chemical composition of 0.59% C, 0.31% Si, 0.73% Mn. A mathematical model for calculating the physical and mechanical properties of steel in the process of hot plastic deformation has been developed and prospects for further development of research in this area have been identified. As a result of modeling, the following functions were obtained: the amount of deformation in the direction of the applied force divided by the initial length of the material. The coefficient of elongation of the material with the actual chemical composition at a temperature of 1250 ± 10 ° C, which was 0.32. When comparing the values of the load that was applied to the GPA in the laboratory and the results of calculations using the developed model, it was found that they have close values of about 45 MPa. This confirms the adequacy of the obtained model.

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