Known as Zr702, the commercially pure zirconium (UNS R60702) is a hafnium-containing commercial grade of zirconium which is widely used in industrial applications such as chemical processing equipment. Due to the exceptional corrosion resistance of zirconium to an extensive range of media, zirconium tubes (usually Zr702) are widely used for the construction of heat exchangers, coolers, condensers, heaters, piping and other boiler & pressure vessel equipment under harsh conditions. The annealed zirconium tubes shall be manufactured to ASTM B523/ ASME SB-523 in either seamless or welded type.

Zirconium tubes of Grade R60702 are applicable to the construction of nuclear facility components of ASME BPVC Section III Classes 2 & 3, with maximum temperature limit of 400°F; and they are also applicable to the construction of pressure vessels of ASME BPVC Section VIII Division I, with maximum temperature limit of 700°F. The poisson’s ratio of Grade R60702 is 0.35 and its density is 0.234 lb/inch³. The chemical composition of Grade R60702 is: Zr+Hf ≥ 99.2%, Hf ≤ 4.5%, Fe+Cr ≤ 0.2%, H ≤ 0.005%, N ≤ 0.025%, C ≤ 0.05%, O ≤ 0.16%. The mechanical properties include: tensile strength ≥ 55 ksi[380 MPa], yield strength ≥ 30 kis[205 MPa], elongation in 2″(50 mm) ≥ 16%.

Maximum Allowable Stresses at Different Temperatures

*Temp.	-20~100	150	200	250	300	350	400
*SMLS	15.7	15.1	13.7	12.4	11.2	10.1	9.1
*Welded	13.4	12.8	11.6	10.5	9.5	8.6	7.7
*Temp.	450	500	550	600	650	700	-
*SMLS	8.3	7.4	6.6	6.0	5.6	5.2	-
*Welded	7.0	6.3	5.6	5.1	4.7	4.5	-

*Temp.: metal temperature, °F, not exceeding; *SMLS/ *Welded: maximum allowable stresses for seamless/welded zirconium tubes of Gr. R60702 respectively, ksi.

Tensile Strength & Yield Strength at Different Temperatures

*Temp.	-20~100	200	300	400	500
*T.S.	55.0	47.9	39.0	31.9	26.6
*Temp.	600	650	700	750	800
*T.S.	23.1	21.8	20.8	19.9	91.2

*Temp.: metal temperature, °F, not exceeding; *T.S.: tensile strengths for seamless & welded zirconium tubes of Gr.R60702, ksi.

*Temp.	-20~100	150	200	250	300	350	400	450
*Y.S.	30.0	25.8	23.1	20.4	18.0	15.9	14.0	12.4
*Temp.	500	550	600	650	700	750	800	-
*Y.S.	11.0	9.9	9.0	8.4	7.9	7.6	7.5	-

*Temp.: metal temperature, °F, not exceeding; *Y.S.: yield strengths for seamless & welded zirconium tubes of Gr.R60702, ksi.