Welding Consumables for 2.25Cr-1Mo-V Refining Reactors

2017 ◽  
Author(s):  
Hideaki Takauchi ◽  
Tomoaki Nakanishi ◽  
Hidenori Nako
Keyword(s):  
High Temperatures ◽  
Temper Embrittlement ◽  
Pressure Vessels ◽  
Creep Rupture ◽  
Hydrogen Attack ◽  
Fine Carbide ◽  
Higher Temperature ◽  
Welding Consumables ◽  
Segregation Of Impurities ◽  
Welding Materials

Owing to the demands for larger-capacity reactor vessels in petroleum plants and higher temperature processes for the upgrade of heavy oil, enhanced 2.25Cr-1Mo, 2.25Cr-1Mo-V and 3Cr-1Mo-V steels, which suit both high temperatures and pressure operations, have been developed and used for heavy-wall pressure vessels since the 1990s. 2.25Cr-1Mo-V steel, which has very special mechanical properties, resistant to both hydrogen attack and embrittlement under high temperatures and pressure environments in particular, has been used since 2000. The specifications for 2.25Cr-1Mo-V steel pressure vessels, such as ASME Sec. VIII and API RP 934-A, have been established and reviewed to enhance the contents [1–2]. In this report, the transition of materials, the welding techniques for hydrocracking reactors and 2.25Cr-1Mo-V welding materials are introduced. Particularly, for these welding materials, in order to improve the creep rupture and temper embrittlement properties, the effectiveness of precipitates is discussed. It was found that fine carbide (MC) in crystal grains improves creep rupture lifetime and MC at the prior austenite (γ) grain boundaries inhibits temper embrittlement caused by the segregation of impurities.

Creep-Rupture Properties, Resistance to Temper Embrittlement and to Attack by Hydrogen of a 1.4 Percent Mn — 0.25 Percent Mo — 0.03 Percent Cb Steel

1975 ◽  
Vol 97 (3) ◽  
pp. 234-244 ◽  
Author(s):  
T. Wada ◽  
D. L. Sponseller
Keyword(s):  
Carbon Steel ◽  
Rupture Strength ◽  
Temper Embrittlement ◽  
Charpy Impact ◽  
Creep Rupture ◽  
Hydrogen Attack ◽  
Boiler Steel ◽  
Rupture Ductility ◽  
Treated Carbon ◽  
Rupture Properties

A laboratory heat of an improved boiler steel containing 0.13 percent C, 1.36 percent Mn, 0.27 percent Mo, 0.03 percent Cb, and 0.010 percent N was prepared; creep-rupture properties, resistance to temper embrittlement and resistance to hydrogen attack were investigated. The rupture strength was much higher than that of carbon steel and columbium-treated carbon steel, but was somewhat lower than that of two European carbon-0.3 percent Mo boiler steels. Creep-rupture ductility was high. The experimental steel exhibited high toughness, especially in the normalized and stress-relieved condition. No temper embrittlement was induced by step-cooling normalized or normalized and stress-relieved material. Good resistance to hydrogen attack was revealed by tests in a hydrogen autoclave at a pressure of 1000 psi (6.9 N/mm2); the steel retained the original Charpy impact toughness after exposures up to 5000 hr at 900 deg F (480 deg C) and 500 hr at 1000 deg F (540 deg C). No blistering or fissuring were observed.

The Use of Vanadium Modified Materials for Reactor Fabrication

2005 ◽  
Author(s):  
Les Antalffy ◽  
Fausto Fusari ◽  
A. Bertoni ◽  
George Miller ◽  
Kenneth Kirkpatrick
Keyword(s):  
Heat Treatment ◽  
Weld Metal ◽  
Temper Embrittlement ◽  
Pressure Vessels ◽  
Post Weld Heat Treatment ◽  
Notch Toughness ◽  
Hydrogen Attack ◽  
Weld Overlay ◽  
Stress Relieving ◽  
Metal Weld

Vanadium modified 2 1/4Cr-1Mo and 3Cr-1Mo alloys used for the fabrication of hydroprocessing reactors offer a number of important advantages over the corresponding conventional alloys. These include increased resistance to hydrogen attack, a lower susceptibility to temper embrittlement, increased resistance to weld overlay disbonding and higher strength resulting in thinner and lighter reactors. Since the first vanadium modified 3Cr-1Mo reactors first went into service in the early 1990’s, vanadium modified alloys have gained acceptance and today more than one hundred and forty vanadium modified reactors and pressure vessels have been placed in service and are operating in severe process environments. Despite the excellent benefits of these materials, they also exhibit less desirable characteristics such as reduced weldability, higher hardnesses in the base metal, weld metal and heat affected zones and the need for higher post weld heat treatment (PWHT) temperatures. Additionally, these materials have a reduced notch toughness at lower temperatures especially in the as welded condition and require intermediate stress relieving (ISR) in lieu of dehydrogenation treatment (DHT) in restrained and highly stressed joints such as nozzle to shell and head welds. These materials also require extra care and effort to be taken during fabrication. The paper presents a serious weld metal cracking problem that occurred with vanadium modified materials during the installation of a nozzle in a restrained and highly stressed weld when only DHT was performed instead of the more beneficial ISR. This fabrication problem is provided as a typical example of problems that can occur during fabrication with vanadium modified materials, and points out that additional care must be taken during fabrication when using these materials. The paper identifies the main causes for the cracking using information based upon mechanical, metallurgical and stress analyses and suggests steps that may be taken to circumvent similar reoccurrences.

Effect of Carbide Content on Temper Embrittlement of 2.25Cr1Mo Steel

2016 ◽  
Author(s):  
Yian Wang ◽  
Guoshan Xie ◽  
Zheng Zhang ◽  
Xiaolong Qian ◽  
Yufeng Zhou ◽  
...  
Keyword(s):  
High Temperature ◽  
Pressure Vessel ◽  
High Stress ◽  
Temper Embrittlement ◽  
Damage Mechanism ◽  
Pressure Vessels ◽  
Nondestructive Method ◽  
Operating Conditions ◽  
Low Alloy Steels ◽  
Carbide Content

Temper embrittlement is a common damage mechanism of pressure vessels in the chemical and petrochemical industry serviced in high temperature, which results in the reduction of roughness due to metallurgical change in some low alloy steels. Pressure vessels that are temper embrittled may be susceptible to brittle fracture under certain operating conditions which cause high stress by thermal gradients, e.g., during start-up and shutdown. 2.25Cr1-Mo steel is widely used to make hydrogenation reactor due to its superior combination of high mechanical strength, good weldability, excellent high temperature hydrogen attack (HTHA) and oxidation-resistance. However, 2.25Cr-1Mo steel is particularly susceptible to temper embrittlement. In this paper, the effect of carbide on temper embrittlement of 2.25Cr-1Mo steel was investigated. Mechanical properties and the ductile-brittle transition temperature (DBTT) of 2.25Cr-1Mo steel were measured by tensile test and impact test. The tests were performed at two positions (base metal and weld metal) and three states (original, step cooling treated and in-service for a hundred thousand hours). The content and distribution of carbides were analyzed by scanning electron microscope (SEM). The content of Cr and Mo elements in carbide was measured by energy dispersive X-ray analysis (EDS). The results showed that the embrittlement could increase the strength and reduce the plasticity. Higher carbide contents appear to be responsible for the higher DBTT. The in-service 2.25Cr-1Mo steel showed the highest DBTT and carbide content, followed by step cooling treated 2.25Cr-1Mo steel, while the as-received 2.25Cr-1Mo steel has the minimum DBTT and carbide content. At the same time, the Cr and Mo contents in carbide increased with the increasing of DBTT. It is well known that the specimen analyzed by SEM is very small in size, sampling SEM specimen is convenient and nondestructive to pressure vessel. Therefore, the relationship between DBTT and the content of carbide offers a feasible nondestructive method for quantitative measuring the temper embrittlement of 2.25Cr-1Mo steel pressure vessel.

High-Pressure Plant for Experimental Hydrogenation Processes

1934 ◽  
Vol 128 (1) ◽  
pp. 5-75 ◽  
Author(s):  
A. T. Barber ◽  
A. H. Taylor
Keyword(s):  
High Pressure ◽  
Experimental Plant ◽  
Hydrogen Attack ◽  
Special Alloy Steels ◽  
Special Alloy ◽  
Continuous Plant ◽  
Complete Disintegration ◽  
Alloy Steels ◽  
Higher Temperature ◽  
Pressure Plant

The paper gives an account of some of the mechanical difficulties experienced in the development and operation of experimental plant for the hydrogenation of coal and tar for the production of motor spirit. Particulars of the various stages of progress are given, from small autoclaves up to a continuous plant capable of producing up to 300 gallons of spirit per day. The pressure plant is operated at 3,000 to 6,000 lb. per sq. in., and at temperatures up to 950 deg. F. Hydrogen produces complete disintegration of the structure of mild steel under the higher temperature conditions. The use of special alloy steels reduces the liability to hydrogen attack, giving longer working life and allowing higher working pressures, but satisfactory service can best be obtained by insulating the pressure-resisting walls from the heating medium so as to avoid heating the metal beyond 200 deg. F. Various methods of making suitable joints for high-pressure pipes and cylinders are described, and the results of microscopic examination of sections of cylinders are given in Appendixes.

scholarly journals Effects of Lowering Si and Impurites on Temper-embrittlement and Creep Rupture Strength in Cr-Mo-V Steel for Turbine Rotor

1986 ◽  
Vol 72 (14) ◽  
pp. 1937-1943
Author(s):  
Masao SHIGA ◽  
Mitsuo KURIYAMA ◽  
Seishin KIRIHARA ◽  
Ryoichi KANEKO ◽  
Yasuo WATANABE
Keyword(s):  
Rupture Strength ◽  
Temper Embrittlement ◽  
Turbine Rotor ◽  
Creep Rupture ◽  
Creep Rupture Strength

scholarly journals Temporal Patterns of Flowering and Pod Set of Determinate Soybean in Response to High Temperature

Agronomy ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 414 ◽  
Author(s):  
Yean-Uk Kim ◽  
Doug-Hwan Choi ◽  
Ho-Young Ban ◽  
Beom-Seok Seo ◽  
Junhwan Kim ◽  
...  
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Temporal Distribution ◽  
Temporal Patterns ◽  
Bimodal Distribution ◽  
Flowering Duration ◽  
Sowing Dates ◽  
Glycine Max L ◽  
Higher Temperature ◽  
Pod Number

Global warming is expected to affect yield-determining factors of soybean (Glycine max (L.) Merr.), including the number of flowers and pods. However, little is known about the effects of high temperature on the temporal patterns of flowering and pod set. Experiments in the temperature-controlled greenhouses were conducted to examine the temporal pattern of flowering in determinate soybean cultivar “Sinpaldalkong” and to assess the effects of high temperature on the flower number, pod-set ratio, and pod number of the early- and late-opened-flowers and their contributions to overall pod number. The experiment comprised five sowing dates in 2013–2015 and four temperature treatments, namely ambient temperature (AT), AT + 1.5 °C, AT + 3.0 °C, and AT + 5.0 °C. Flowering duration (i.e., days between the first flowering and the last flowering) was extended by higher temperature and earlier sowing. The temporal distribution of flowering showed a bimodal distribution except for the experiment with the shortest flowering duration, i.e., second sowing in 2014. More flowers were produced in the late flowering period at high temperatures; however, most of these late-opened-flowers failed to reproduce, regardless of temperature conditions, resulting in a negligible contribution to the overall pod number. For the early-opened-flowers, the number of flowers was not significantly affected by temperature, while the pod-set ratio and pod number decreased with high temperatures resulting in a decrease in the overall pod number at temperatures above 29.4 °C.

Preparation of Butadiene

1928 ◽  
Vol 1 (2) ◽  
pp. 208-210
Author(s):  
Stanley Francis Birch
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Liquid Phase ◽  
High Temperatures ◽  
Vapor Phase ◽  
Complex Mixture ◽  
Higher Temperature ◽  
Oil Gas

Abstract OF THE numerous methods available for the preparation of butadiene in the laboratory, those described by Thiele and by Ostromuislenskii are probably the most convenient. Both, however, suffer from the disadvantages which usually characterize operations at comparatively high temperatures; the exact conditions are difficult to find, the process is long and tedious, and finally involves the separation of the required material from a complex mixture. It has long been known that butadiene occurs in the various products obtained when oils are heated to a high temperature. Caventou first isolated butadiene in the form of its tetrabromide from illuminating gas, and Armstrong and Miller definitely established the presence of butadiene in the liquid obtained by compressing oil gas. The work of numerous later investigators has confirmed their results and has shown that the more drastic the heat treatment to which the oil is submitted the greater is the tendency for butadiene to be formed. For this reason vapor-phase cracking of petroleum, which is carried out at a much higher temperature than liquid-phase cracking, yields products specially rich in butadiene.

The “Solidification” of Grain Boundaries with Increasing Temperature

1994 ◽  
Vol 357 ◽  
Author(s):  
Witold Lojkowski ◽  
Bogdan Palosz
Keyword(s):  
Solid State ◽  
Melting Point ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
High Temperatures ◽  
Low Temperatures ◽  
Melting Behavior ◽  
Wetting Transitions ◽  
Increasing Temperature ◽  
Segregation Of Impurities

AbstractThe aim of the paper is to explain the recently observed de-wetting grain boundary transition with increasing temperature. On the example of a bicrystal from the Fe-6at.%Si alloy, it was found recently that as temperature is increased, the following GB transitions take place: “solid” (or regular) GB-→“premelted” GB →“solid” GB. At the same time the wetting/de-wetting transitions have taken place. Another example of such GB behavior was discovered during sintering of alumina. The inverse melting behavior is explained as follows: low melting point impurities cause GB premelting at low temperatures, However de-segregation of impurities at high temperatures causes return of the GB structure to its regular “solid” state.

Progress in the Design of an Improved High-Temperature 1 Percent CrMoV Rotor Steel

1990 ◽  
Vol 112 (1) ◽  
pp. 99-115 ◽  
Author(s):  
R. L. Bodnar ◽  
J. R. Michael ◽  
S. S. Hansen ◽  
R. I. Jaffee
Keyword(s):  
Tensile Strength ◽  
High Temperature ◽  
Room Temperature ◽  
Rupture Strength ◽  
Temper Embrittlement ◽  
Creep Rupture ◽  
Rotor Steel ◽  
Creep Rupture Strength ◽  
Austenitizing Temperature ◽  
Creep Ductility

Silicon-deoxidized, tempered bainitic 1 percent CrMoV steel is currently used extensively for high-temperature steam turbine rotor forgings operating at temperatures up to 565°C due to its excellent creep rupture properties and relative economy. There is impetus to improve the creep rupture strength of this steel while maintaining its current toughness level and vice versa. The excellent creep rupture ductility of the low Si version of this steel allows the use of a higher austenitizing temperature or tensile strength level for improving creep rupture strength without loss in creep ductility or toughness. When the tensile strength of this steel is increased from 785 to 854 MPa, the creep rupture strength exceeds that of the more expensive martensitic 12CrMoVCbN steel currently used for high-temperature rotor applications where additional creep rupture strength is required. The toughness of 1 percent CrMoV steel is improved by lowering the bainite start (Bs) temperature in a “superclean” base composition which is essentially free of Mn, Si, P, S, Sb, As and Sn. The Bs temperature can be lowered through the addition of alloying elements (i.e., C, Ni, Cr, and Mo) and/or increasing the cooling rate from the austenitizing temperature. Using these techniques, the 50 percent FATT can be lowered from approximately 100°C to below room temperature, which provides the opportunity to eliminate the special precautionary procedures currently used in the startup and shutdown of steam turbines. The most promising steels in terms of creep rupture and toughness properties contain 2.5 percent Ni and 0.04 percent Cb (for austenite grain refinement and enhanced tempering resistance). In general, the creep rupture strength of the superclean steels equals or exceeds that of the standard 1 percent CrMoV steel. In addition, the superclean steels have not been found to be susceptible to temper embrittlement, nor do they alter the room temperature fatigue crack propagation characteristics of the standard 1 percent CrMoV steel. These new steels may also find application in combination high-temperature-low-temperature rotors and gas turbine rotors.

Creep Life of Ceramic Components Using a Finite Element Based Integrated Design Program (CARES/CREEP)

1996 ◽  
Author(s):  
Lynn M. Powers ◽  
Osama M. Jadaan ◽  
John P. Gyekenyesi
Keyword(s):  
Finite Element ◽  
High Temperatures ◽  
Failure Modes ◽  
Integrated Design ◽  
Systems Design ◽  
Creep Rupture ◽  
Creep Life ◽  
Time Step ◽  
Design Program ◽  
Structural Applications

The desirable properties of ceramics at high temperatures have generated interest in their use for structural applications such as in advanced turbine systems. Design lives for such systems can exceed 10,000 hours. The long life requirement necessitates subjecting the components to relatively low stresses. The combination of high temperatures and low stresses typically places failure for monolithic ceramics in the creep regime. The objective of this paper is to present a design methodology for predicting the lifetimes of structural components subjected to creep rupture conditions. This methodology utilizes commercially available finite element packages and takes into account the time varying creep strain distributions (stress relaxation). The creep life of a component is discretized into short time steps, during which, the stress and strain distributions are assumed constant. The damage is calculated for each time step based on a modified Monkman-Grant creep rupture criterion. Failure is assumed to occur when the normalized accumulated damage at any point in the component is greater than or equal to unity. The corresponding time will be the creep rupture life for that component. Examples are chosen to demonstrate the CARES/CREEP (Ceramics Analysis and Reliability Evaluation of Structures/CREEP) integrated design program which is written for the ANSYS finite element package. Depending on the components size and loading conditions, it was found that in real structures one of two competing failure modes (creep or slow crack growth) will dominate. Applications to benchmark problems and engine components are included.

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