Joint strength

The tensile strength in the joint part shown Fig.ll has less than the maetrial strength. As for this, joint strength is thought to be a decrease more than the strength of Ti because of an increase in the intermetallic compound of TiC that a little brittle. 

In welding copper itself, the copper must be free of oxygen if the joint strength is required to be equal to that of the base metal. Copper alloys and can be welded with the shielded-metal arc, gas—metal arc, and gas—tungsten arc process. 

Adhesives and Sealants. Most industrial adhesives contain surface active components and additives, and air entrainment during their mechanical appHcation can significantly reduce joint strength. Defoamers are usually formulated into adhesives to protect users against such difficulties. Additional benefits, such as improved uniformity of products, increased throughput and reduced labor costs can also result from the use of defoamers during adhesive appHcation. The footwear and nonwoven fabric industries are extensive users of defoamers in this way. 

Another major area of use is in the field of adhesives. The main attractions of the material are the absence of a need for mastication, easy solvation of the polymer, which is supplied in a crumb form, the production of low-viscosity solutions and high joint strength. In conjunction with aromatic resins they are used for contact adhesives whilst with aliphatic resin additives they are used for permanently tacky pressure-sensitive adhesives. In addition to being applied from solution they may be applied as a hot melt. 

Fig. I. Comparison of unprimed and eleetroprimed single lap-shear adhesive joint strengths for steel coupons bonded with imidazole-cured epoxy [43].

Note Most buttress thread couplings will not develop the highest minimum joint strength unless couplings of the next higher order are specified. (See API Specification 5A for more detailed information.)... 

Values for collapse resistance, internal yield pressure, pipe body, and joint strength for steel grades as in Table 4-141 are given in Table 4-150. Table 4-150 is directly taken from API Bulletin 5C2, 17th Edition, 1980. Formulas and procedures for calculating the values in Table 4-150 are given in Bulletin 5C3 [152] and are as follows ... 

Buttress Thread Casing Joint Strength. Buttress thread casing joint strength is calculated from formulas 4-318 and 4-319. The lesser of the values obtained from the two formulas governs. 

Extreme-line Casing Joint Strength. Extreme-line casing joint strength is calculated from... 

Steel grade Unit weight (Ib/ft) Cross-sectional sraa (In.) Collapse pressure resistance Burst pressure resistance Joint strength (10> lb) Pipe body strength (10> lb)... 

Step 2. Maximum length of Section 4 due to its Joint strength is... 

The weld joint strength reduction factor is the ratio of the nominal stress to cause failure of the weld joint to that of the base material for the same duration. In the absence of more applicable data (e.g., creep testing), the factor shall be taken as 1.0 at temperatures equal or colder than 510°C (950°F), and 0.5 at 815°C (1,500°F) for all materials. The strength reduction factor shall be linearly interpolated for intermediate temperatures. The designer is responsible for determining weld joint strength reduction factors for temperatures warmer than 815°C (1,500°F). 

Creep testing of weld joints to determine weld joint strength reduction factors should be full thickness crossweld specimens with test durations of at least 1 000 h. Full thickness tests shall be used unless the designer otherwise considers effects such as stress redistribution across the weld. 

T = pipe wall thickness (measured or minimum per purchase specification) t — pressure design thickness, as calculated in accordance with para. IP-3.2.1 for internal pressure or as determined in accordance with para. IP-3.2.2 for external pressure tm — minimum required thickness, including mechanical, corrosion, and erosion allowances W = weld joint strength reduction factor per para. IP-2.2.10... 

Sf = product SEWMj [of the stress value, S the appropriate quality factor, E, from Tables IX-2 or IX-3A weld joint strength reduction factor per para. IP-2.2.10(e) and the performance factor, Mj(see Mandatory Appendix IX)] for flange or pipe material see para. IP-2.2.7(c). 

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