Effect of Partitioning Temperature on Work Hardening Behavior of Q&P Steels

2011 ◽  
Vol 299-300 ◽  
pp. 403-407 ◽  
Author(s):  
Shuai Zhu ◽  
Yong Lin Kang ◽  
Kang Kang Ren ◽  
Sheng Ci Li

Study on the instantaneous n-value of 0.3C-1.5Mn-1.5Si steel subjected to 1-step quenching and partitioning process (Q&P) is presented. The result indicated that the curves of instantaneous n-value vs. true strain could be divided into three stages. First, the instantaneous n-value shows a rapid decrease, then a comparative stable stage was observed due to the TRIP phenomenon of retained austenite, at last the instantaneous n-value decreases sharply to zero when necking appearance. The relationship of instantaneous n-value and partitioning temperature (PT) was analyzed; n-value decreased along with the rise of PT due to a higher carbon concentration and lower volume fraction of retained austenite was obtained at higher PT which could influence the uniform elongation and the stability of retained austenite.

2018 ◽  
Vol 941 ◽  
pp. 251-256
Author(s):  
Hong Shuang Di ◽  
Yong Gang Deng ◽  
Jian Ping Li

One industrially C-Mn steel was studied in the present work. The Mn pre-partitioning process during continuous annealing was used. The results showed that the stability of retained austenite is increased because of the Mn pre-partitioning. The amount of retained austenite was about 5%, when increase the partition time to 100s. With the increase of the partition time, the amount of retained austenite increases, the tensile strength decreases, the yield strength and elongation both increase. Compared with quenching and tempering (Q&T) process, the tested steel after pre-partitioning quenching and partitioning (PQ&P) process has higher uniform elongation and the product of strength and elongation (UTS×TEL).


Author(s):  
З.С. САНОВА

В статье представлены материалы о взаимосвязи продолжительности продуктивного использования коров с характеристикой устойчивости к деградации, с возрастом отела и удоем. В исследованной, разнородной по происхождению, группе животных для прогноза продуктивного периода коров, обусловленного устойчивостью к деградации и возрастом первого отела, пригодно уравнение регрессии, аргументами в котором являются индекс устойчивости, возраст первого отела в первой и второй степенях. Коэффициент корреляции межу предсказанными значениями продуктивного периода и его фактическими величинами в I группе составляет 0,502, во II - 0,604. При этом крайние варианты прогнозируются со статистическими ошибками 5 мес при оценке индекса устойчивости по 2 лактациям и 4,1 мес по 3, а средние варианты, соответственно, 1,6 и 1,51 мес. Индекс устойчивости к процессу старения является важной характеристикой биологических особенностей коров, определяющий их продуктивное долголетие. Его оценка по первым 2 и 3 лактациям имеет прямолинейную связь с продуктивным периодом (r=0,4109 и r=0,5270), соответственно. Зависимость продуктивного периода от возраста первого отела криволинейная — с увеличением возраста первого отела сокращается срок продуктивного использования, при возрасте первого отела более 1400 дней срок продуктивного использования колеблется от 1,33 до 1,41 лактации. Коэффициент корреляции между этими характеристиками коров составляет - 0,2164 в I и - 0,2620 во II группах. The article presents materials about the relationship of the duration of productive use of cows with the characteristic of resistance to degradation, with the age of calving and milk yield. In the studied group of animals, which is heterogeneous in origin, the regression equation is suitable for predicting the productive period of cows due to resistance to degradation and the age of the first calving, the arguments of which are the stability index, the age of the first calving in the first and second degrees. The correlation coefficient between the predicted values of the productive period and its actual values in group I is 0.502, in group II - 0.604. At the same time, the extreme variants are predicted with statistical errors of 5 months when evaluating the stability index for 2 lactations and 4.1 months for 3, and the average variants, respectively, are 1.6 and 1.51 months. The index of resistance to the aging process is an important characteristic of the biological characteristics of cows, which determines their productive longevity. Its estimate for the first 2 and 3 lactations has a direct relationship with the productive period (r=0.4109 and r=0.5270), respectively. The dependence of the productive period age at first calving curvilinear with increasing age at first calving reduces the time to productive use, while age at first calving of more than 1400 days, the period of productive use ranges from 1.33 to 1.41 lactation. The correlation coefficient between these characteristics of cows is-0.2164 in I and-0.2620 in II groups.


2019 ◽  
Vol 64 ◽  
pp. 03013 ◽  
Author(s):  
Ilya V. Dunichkin ◽  
Emanuele Naboni ◽  
Anna E. Korobeinikova ◽  
Olga I. Poddaeva

Subject of research: visualization of the wind regime of residential buildings on the slope area in the Arctic. Goals: the purpose of the study is to identify the problems of visualization of the wind regime on the slopes and the analysis of patterns of airflow around the sloping territories, affecting the comfort of pedestrians. Materials and methods: airflow patterns of slope areas with different characteristics and comfort assessment for humans are analyzed in the course of work. Geotechnical methods are presented in solving the problems of wind erosion and the stability of hillsides and complex terrain within the city limits. Results: The importance and novelty of the research in studying the relationship of slope geometry and environmental quality, as a decrease in comfort inevitably leads to a decrease in the development of nearby urban areas in settlements on the coast of the Arctic Ocean, problems with climate and local climate, as well as a decrease in the quality of life of people. The article considers the relationship of plastic relief with the aeration regime of the territory, the dependence of aerodynamic roughness on their height, features of aeration of the slope and hilly terrain, factors affecting the direction and speed of the wind and methods for studying the aeration regime of slope areas. Findings: The possibilities of applying existing approaches to research and visualization for slope areas are demonstrated. The direction of development of the technique for visualization of slope areas has been determined.


2011 ◽  
Vol 90-93 ◽  
pp. 2389-2392
Author(s):  
Hai Yan Ju ◽  
Gui Qing Gao ◽  
Jian Hua Li ◽  
Jiang Qian Zhao ◽  
Zhang Ming Li

Because the relationship is not considered between physical behavior and cross sections of bars, the conventional reinforced earth retaining wall design based on constant value would lead to some limitations: the haul-resistant coefficient of the top wall is not enough, but it goes beyond at the bottom of retaining wall. In the paper, considering the SARMA method, based on computing formula of traditional slope stability, the detailed programme is realized by the language of FORTRAN, it can make up deficiency that lies in the tradition reinforced earth retaining wall by considering the relationship of physical behavior and cross sections, lengths and layers of bars. Finally, the system program has been applied to a slope treatment project in Guangzhou. Compared with the design method of traditional regulations, it is demonstrated that the optimum length required is obtained, the cross section and length of bars are fully used, and the design is simplified.


2021 ◽  
Vol 30 (1) ◽  
Author(s):  
Tuan Minh Tran ◽  
Quang Huy Nguyen

In recent years, experimental and numerical researches on the effect of blasting pressure on the stability of existing tunnels was widely obtained. However, the effect of the blasting pressure during excavation a new tunnel or expansion old tunnels on an existing tunnel has disadvantages and still unclear. Some researches were carried out to study the relationship of the observed Peak Particle Velocity (PPV) on the lining areas along the existing tunnel direction, due to either the lack of in situ test data or the difficulty in conducting field tests, particularly for tunnels that are usually old and vulnerable after several decades of service. This paper introduces using numerical methods with the field data investigations on the effect of the blasting in a new tunnel on the surrounding rock mass and on the existing tunnel. The research results show that not only predicting the tunnel lining damage zone under the impact of blast loads but also determination peak maximum of explosion at the same time at the surface of tunnel working.


1976 ◽  
Vol 7 (3) ◽  
pp. 161-180 ◽  
Author(s):  
A. J. Reynolds

This paper reviews work on the stability of a particulate stream bed to the erosive attack of a flow with a free surface. Attention is given to the development of the hydraulic, the potential-flow and the rotational-flow models, and to the roles of phase lags and transport laws. The relationship of the stability theory to the ultimate form of the stream bed is discussed, and the current level of understanding of bed features is examined. Some investigations relating to a wider range of erosive processes are noted, and an extensive bibliography is provided.


2021 ◽  
Vol 76 (6) ◽  
pp. 445-457
Author(s):  
R. Schneider ◽  
S. Kaar ◽  
S. Schneider ◽  
D. Krizan ◽  
C. Sommitsch

Abstract In contrast to quenching and tempering (Q&T), with quenching to room temperature, quenching and partitioning (Q&P) usually applies quenching to a temperature between Ms and room temperature. To stabilize a sufficient amount of retained austenite (RA), carbon diffusion from martensite into austenite and a prevention of cementite formation takes place during the successive partitioning step. Larger amount of RA, and its transformation into martensite during plastic deformation, provides Q&P treated steels with an enhanced combination of strength and ductility. In this investigation, the effect of different Q&T and Q&P treatments on the hardness-toughness relationship was determined. These results are compared with the RA contents and mechanical properties provided by tensile testing. The obtained results clearly demonstrate that the optimum parameters for strength and ductility do not match with the best combinations of hardness and toughness. Furthermore, the stability of the RA plays an important role in the understanding of toughness properties of the investigated Q&P steels.


Behaviour ◽  
1984 ◽  
Vol 91 (1-3) ◽  
pp. 115-126 ◽  
Author(s):  
J. Lamprecht

AbstractAllogrooming, dueting and other behaviours observed only between pair or group members are often said to reinforce or strengthen social bonds, yet the strength of these bonds was not measured independently. 'Bond strength' should reflect the stability of an attachment relationship and thus the probability of a permanent separation from the partner. The latter is a function of opportunity or external force as well as of an internal 'divorce tendency'. Only the divorcc tendency is inversely related to that motivational variable which can be called 'bond strength'. To find a behavioural measure of individual divorce tendency, the relationship of hand-reared bar-headed goslings (Anser indicus) to their human foster parents was investigated in four experiments. The following results were obtained: (1) The subjects (n = 18) significantly preferred their own, familiar foster parent (Hp) to a less familiar person (Hu). (2) This was also true when the Hu was the preferred Hp of another group of goslings, indicating that familiarity and not his suitability as a 'goose parent' is the relevant factor. (3) Alone with one person on a lawn, all goslings (n = 12) also maintained proximity when this was an Hu, indicating a bond to him also. Median distances maintained to Hp and Hu did not differ significantly, and were therefore no indicators of a gosling's preference. But the distress calling rate was significantly higher and the feeding rate significantly lower when a gosling was with an Hu than when with its Hp. (4) Distress calling rate in the presence of a stationary person was also a good indicator of a gosling's (n = 15) tendency to leave him and follow a slowly moving stranger. Approaches towards the stranger were significantly longer when the stationary person was an Hu than when it was the Hp. The amount of distress calling in the presence of an Hu was positively correlated (p<0.01) with the distance that the subjects later moved towards the stranger. The distress calling rate therefore is a good relative measure of a gosling's tendency to abandon a particular object, this tendency reflecting what we may call the strength of a bond or attachment.


Ramus ◽  
1977 ◽  
Vol 6 (2) ◽  
pp. 83-102 ◽  
Author(s):  
Eva Stehle Stigers

Catullus described a full emotional circle in his short life from delight in unconstrained aesthetic sensuality free of socially-defined patterns (cc. 5, 6, 13 for example) to longing for a stable bond in the relationship of man to woman. He pictured such a bond as placed within the traditional Roman frame of marriage and home, but cast in a personal mold; he wanted to preserve his aesthetic and sensual response to a woman while combining it somehow with the stability and intimacy appropriate to friendship (amare and bene velle). Poems 72 and 87, for instance, directly express the ideal in acknowledging its absence from Catullus' relations with Lesbia.Catullus liked to feel that the possibility of complete union was what he offered Lesbia. Perhaps it was his inability to fashion a compelling synthesis of sexual intimacy and friendship with her that led him to write a series of poems exploring attempts, mainly failures, at full reciprocal love. The successful attempts are idyllic or mythic (Septimius and Acme, Peleus and Thetis, neither unambiguously positive). The failures come, in Catullus' portrayal, when union founders on the obstacle of the narcissistic personality, the man or woman unable to forfeit autonomy, desirous of holding others in thrall without being himself held. Catullus' highly developed sensitivity to narcissism must be a reaction to its prominence in the character of a certain kind of sexually attractive individual, the one who is alluring but uncapturable, the kind of woman, like Lesbia, with whom Catullus sought union. Catullus conveys the quality of narcissism in such a character in part through the image of the flower (appropriately, considering the source of the modern name for it).


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