Considerations for Selecting the Optimum Bolt Assembly Stresses for Piping Flanges

2006 ◽  
Author(s):  
Warren Brown ◽  
David Reeves
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Stress Level ◽  
Good Practice ◽  
Stress Range ◽  
Practical Application ◽  
Alternative Approach ◽  
Bolt Stress ◽  
Standard Value ◽  
The Difference

In order to minimize the likelihood of leakage from flanged piping joints, it is a good practice to maximize the initial bolt assembly stress. Present bolting guidelines (ASME PCC-1 [1]) use a standard percent of bolt yield to set the assembly stress level. This approach does not allow for the difference in strength between standard pipe flange sizes, differences in material yield strengths (carbon steel versus stainless steel), raised face (RF) versus ring type joint (RTJ) flange configurations and the actual gasket stress achieved across all flange sizes and classes. Since there is no assessment of stresses, such an approach may cause failure of joint components. In addition, because the standard percentage of bolt yield technique does not look at gasket stress, it is prone to gasket leakage due to low stress or gasket destruction due to over-compression for some joints. In addition, some joints may require bolt loads well in excess of the standard value to develop an acceptable gasket stress level in order to prevent leakage. This paper examines an alternative approach, based on the actual gasket and flange stresses. The approach examines the minimum and maximum gasket stress levels to determine what bolt stress range is acceptable and then looks at the flange stresses and flange deformation issues to ensure that the flange will not be permanently damaged, while maximizing the specified bolt load. The practical application of this method is in the development of standard bolt assembly stress (or torque) tables for standard pipe flanges using a given gasket type.

An Update on Selecting the Optimum Bolt Assembly Stress for Piping Flanges

2007 ◽  
Author(s):  
Warren Brown ◽  
David Reeves
Keyword(s):  
Stress Level ◽  
Good Practice ◽  
Element Analysis ◽  
Elastic Plastic ◽  
Load Limit ◽  
Component Strength ◽  
Standard Value ◽  
The Difference ◽  
Common Application

In order to minimize the likelihood of leakage from flanged piping joints, it is a good practice to maximize the initial bolt assembly stress. Present bolting guidelines (ASME PCC-1 [1]) outline the use of a percent of bolt yield across all flange sizes and classes to set the assembly stress level. These guidelines do indicate that aspects such as component strength and gasket stress should be considered, however the most common application of the approach is to use a standard percentage of bolt yield across all flange sizes and classes. This approach does allow for adjustment for differences in material yield strengths (carbon steel versus stainless steel) and raised face (RF) versus ring type joint (RTJ) flange configurations. It does not, however, adjust for the difference in strength between standard pipe flange sizes nor the actual gasket stress achieved across all flange sizes and classes. Since there is no assessment of flange strength, such an approach may cause failure of joint components. In addition, because the standard percentage of bolt yield technique does not look at gasket stress, it is prone to gasket leakage due to low stress or gasket destruction due to over-compression for some joints. In addition, some joints may require bolt loads well in excess of the standard value to develop an acceptable gasket stress level in order to prevent leakage. This paper is a continuation of the paper presented during PVP 2006 in Vancouver (Brown [2]), which examined the variables that must be considered and drew some preliminary conclusions regarding the use of flange stress limits in determining the maximum allowable bolt load for a given flange size. Subsequent to writing that paper, further investigation found that the code calculated flange stresses are a poor indicator of the maximum acceptable bolt load. The most practical measure of this load is obtained by using elastic-plastic finite element analysis (FEA) to determine the point of gross plastic deformation of the flange. This paper details the maximum bolt load limit results of elastic-plastic FEA on most sizes of standard ASME weld neck flange sizes. The practical application of this method is in the development of standard bolt assembly stress (or torque) tables for standard pipe flanges using a given gasket type. In addition, a new code equation and additional limits are developed, by comparison to the elastic-plastic FEA results, which allow the determination of the maximum assembly bolt load for non-standard weld-neck flanges and standard weld-neck flanges with different bores, materials or gaskets than used in the elastic-plastic FEA presented in this paper.

scholarly journals Characteristic Evaluation on Bolt Stress by Ultrasonic Nondestructive Methods

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Qinxue Pan ◽  
Shuai Liu ◽  
Xiao Li ◽  
Chunguang Xu
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Axial Stress ◽  
Low Carbon Steel ◽  
Nondestructive Method ◽  
Load Factor ◽  
Low Carbon ◽  
Longitudinal Waves ◽  
Bolt Stress ◽  
Good Agreement

Based on the acoustoelasticity theory, a certain relationship exists between ultrasonic velocity and stress. By combining shear and longitudinal waves, this paper provides a nondestructive method of evaluating axial stress in a tightened bolt. For measuring the bolt axial stress in different situations, such as under low or high loads, this paper provides guidelines for calculating the stress for a given load factor. Experimental and calculated results were compared for three bolt test samples: an austenitic stainless steel bolt (A2-70) and low-carbon steel 4.8 and 8.8 bolts. On average, the experimental results were in good agreement with those obtained through calculations, thus providing a nondestructive method for bolt stress measurements.

Pyrolytic carbon filaments and associated catalytic particles formed in steel tubes

1984 ◽  
Vol 42 ◽  
pp. 662-663
Author(s):  
Y. L. Chen ◽  
J. R. Bradley
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Catalyst Particle ◽  
Pyrolytic Carbon ◽  
Plain Carbon Steel ◽  
304 Stainless Steel ◽  
Hydrocarbon Gases ◽  
Steel Tubes ◽  
Filamentous Carbon ◽  
Carbon Filaments

Considerable effort has been directed toward an improved understanding of the production of the strong and stiff ∼ 1-20 μm diameter pyrolytic carbon fibers of the type reported by Koyama and, more recently, by Tibbetts. These macroscopic fibers are produced when pyrolytic carbon filaments (∼ 0.1 μm or less in diameter) are thickened by deposition of carbon during thermal decomposition of hydrocarbon gases. Each such precursor filament normally lengthens in association with an attached catalyst particle. The subject of filamentous carbon formation and much of the work on characterization of the catalyst particles have been reviewed thoroughly by Baker and Harris. However, identification of the catalyst particles remains a problem of continuing interest. The purpose of this work was to characterize the microstructure of the pyrolytic carbon filaments and the catalyst particles formed inside stainless steel and plain carbon steel tubes. For the present study, natural gas (∼; 97 % methane) was passed through type 304 stainless steel and SAE 1020 plain carbon steel tubes at 1240°K.

Estimation of Some Mechanical Properties for Similar & Dissimilar Welded Joints

2014 ◽  
Vol 2 (1) ◽  
pp. 59-76
Author(s):  
Abdullah Daie'e Assi
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Austenitic Stainless Steel ◽  
Base Metal ◽  
Welded Joints ◽  
Plate Thickness ◽  
Low Carbon Steel ◽  
Dissimilar Metals ◽  
Low Carbon ◽  
Steel Type

This research deals with the choice of the suitable filler metal to weld the similar and dissimilar metals (Low carbon steel type A516 & Austenitic stainless steel type 316L) under constant conditions such as, plate thickness (6 mm), voltage (78 v), current (120 A), straight polarity. This research deals with three major parts. The first parts Four types of electrodes were used for welding of dissimilar metals (C.St A516 And St.St 316L) two from mild steel (E7018, E6013) and other two from austenitic stainless steel (E309L, E308L) various inspection were carried out include (Visual T., X-ray T., δ- Ferrite phase T., and Microstructures T.) and mechanical testing include (tensile T., bending T. and micro hardness T.) The second parts done by used the same parameters to welding similar metals from (C.St A516) Or (St.St 316L). The third parts deals with welding of dissimilar weldments (C.St And St.St) by two processes, gas tungsten are welding (GTAW) and shielded metal are welding (SMAW).        The results indicated that the spread of carbon from low carbon steel to the welding zone in the case of welding stainless steel elect pole (E309L) led to Configuration Carbides and then high hardness the link to high values ​​compared with the base metal. In most similar weldments showed hardness of the welding area is  higher than the hardness of the base metal. The electrode (E309L) is the most suitable to welding dissimilar metals from (C.St A516 With St.St 316L). The results also showed that the method of welding (GTAW) were better than the method of welding (SMAW) in dissimilar welded joints (St.St 316L with C.St A516) in terms of irregular shape and integrity of the welding defects, as well as characterized this weldments the high-lift and resistance ductility good when using the welding conditions are similar.

ATI 409HP

Alloy Digest ◽  
2013 ◽  
Vol 62 (2) ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Carbon Steel ◽  
Physical Properties ◽  
Tensile Properties ◽  
Ferritic Stainless Steel ◽  
Temperature Performance ◽  
End Use ◽  
Oxidation And Corrosion

Abstract ATI 409HP (UNS S40900) ferritic stainless steel was introduced by ATI Allegheny Ludlum to provide improved oxidation and corrosion resistance for automotive exhaust systems in comparison to carbon steel. The alloy was designated "MF-1", indicating its end use: automotive mufflers. The good fabricability of this alloy, combined with its basic corrosion resistance and economy have significantly broadened the utility of ATI 409HP stainless steel. ATI 409HP consists of four grades: UNS S40900, S40910, S40920, and S40930. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, machining, and joining. Filing Code: SS-1135. Producer or source: Allegheny Technologies Inc..

SANDVIK 3R12/4L7

Alloy Digest ◽  
1996 ◽  
Vol 45 (7) ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Carbon Steel ◽  
Black Liquor ◽  
Heat Treating ◽  
304L Stainless Steel ◽  
Design Load ◽  
Recovery Boilers ◽  
Major Application ◽  
Outside Diameter

Abstract Sandvik 3R12/4L7 is a composite tube consisting of type 304L stainless steel for corrosion resistance on the outside diameter and having carbon steel (A210 Gr. A1) as the inside component for both water wetted service and the design load. The major application is tubing to handle the corrosive conditions in black liquor recovery boilers. This datasheet provides information on composition, physical properties, microstructure as well as fatigue. It also includes information on forming, heat treating, and joining. Filing Code: SA-482. Producer or source: Sandvik.

AK STEEL 409 ULTRA FORM

Alloy Digest ◽  
2007 ◽  
Vol 56 (4) ◽  
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Carbon Steel ◽  
Physical Properties ◽  
Tensile Properties ◽  
Corrosion Protection ◽  
Automotive Exhaust ◽  
Standard Type ◽  
Temperature Performance ◽  
Complex Shapes

Abstract AK Steel 409 Ultra Form was created for applications needing oxidation or corrosion protection beyond the capability of carbon steel and some coated steels. AK Steel 409 Ultra Form is more formable than standard Type 409 stainless steel and is particularly suitable for parts requiring more complex shapes and improved weldability. Examples of applications include automotive exhaust tubing and stampings. This datasheet provides information on physical properties, hardness, elasticity, and tensile properties as well as deformation. It also includes information on high temperature performance as well as forming and joining. Filing Code: SS-990. Producer or source: AK Steel, Butler Operations.

Interfacial Bonding Behavior of Stainless Steel / Carbon Steel in Cold Rolling Process

2020 ◽  
Vol 982 ◽  
pp. 121-127
Author(s):  
Shuo Li ◽  
Qing Dong Zhang
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Great Influence ◽  
Rolling Process ◽  
Interfacial Bonding ◽  
304 Stainless Steel ◽  
Nanoindentation Test ◽  
Real Contact Area ◽  
Steel Matrix ◽  
Bonding Quality

A cylindrical indenter was designed to simulate the roller and 304 stainless steel / Q235A carbon steel plate with different roughness were bonded together. The interfacial bonding behavior was investigated by SEM, ultrasonic “C” scanning detection and nanoindentation test. The result reveal that with the increase of contact pressure between interfaces, the atoms of dissimilar metals begin to diffuse across interfaces in some regions, then form island-like bonding regions, and eventually extend to the whole interface. There are no obvious cracks on the surface of stainless steel and carbon steel after deformation. The cold roll-bonding mechanism of stainless steel and carbon steel is that elements on both sides of the interface diffuse and form a shallow diffusion layer under pressure to ensure the joint strength, and the joint bonding strength is greater than the strength of carbon steel matrix. In addition, the surface morphology of base metal has a great influence on the interfacial bonding quality. The higher surface roughness values increases the hardening degree of rough peak, which makes real contact area difficult to increase and reduce the interfacial bonding quality.

scholarly journals Scanning Accuracy of Bracket Features and Slot Base Angle in Different Bracket Materials by Four Intraoral Scanners: An In Vitro Study

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 365
Author(s):  
Seon-Hee Shin ◽  
Hyung-Seog Yu ◽  
Jung-Yul Cha ◽  
Jae-Sung Kwon ◽  
Chung-Ju Hwang
Keyword(s):  
Stainless Steel ◽  
In Vitro Study ◽  
Sem Images ◽  
Polycrystalline Alumina ◽  
Base Angle ◽  
Accurate Expression ◽  
Dental Model ◽  
Alumina Composite ◽  
The Difference

The accurate expression of bracket prescription is important for successful orthodontic treatment. The aim of this study was to evaluate the accuracy of digital scan images of brackets produced by four intraoral scanners (IOSs) when scanning the surface of the dental model attached with different bracket materials. Brackets made from stainless steel, polycrystalline alumina, composite, and composite/stainless steel slot were considered, which have been scanned from four different IOSs (Primescan, Trios, CS3600, and i500). SEM images were used as references. Each bracket axis was set in the reference scan image, and the axis was set identically by superimposing with the IOS image, and then only the brackets were divided and analyzed. One-way analysis of variance (ANOVA) was used to compare the differences. The difference between the manufacturer’s nominal torque and bracket slot base angle was 0.39 in SEM, 1.96 in Primescan, 2.04 in Trios, and 5.21 in CS3600 (p < 0.001). The parallelism, which is the difference between the upper and lower angles of the slot wall, was 0.48 in SEM, 7.00 in Primescan, 5.52 in Trios, 6.34 in CS3600, and 23.74 in i500 (p < 0.001). This study evaluated the accuracy of the bracket only, and it must be admitted that there is some error in recognizing slots through scanning in general.

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