Elevated Temperatures

Which materials?

BPVSC SEC-IIA materials

Range is depended on the material type and activities with the materials.

In metal roll mill low temperature is when size reduction performed iron or steel will flake because of work hardening.

Moderate temperature is it does not achieve 25 size reduction without crack and high is when uniformity in size reduction is loosed.

In glass red temperature is moderate. Below red is low and white is high for glass melter.

Glass user a temperature less than glass transition temperature is low glass transition to 100oC is moderate and above that is high

In plastic low is below glass transition temperature of Tg and high is above glass transition temperature of plastic. Low is generally 25% to 50 % of glass transition temperature based on polymer chemistry

All the above is rules of thumb but they work

Please, Wich one is the section and point in ASME Code

"ASME refers to low temperature, moderate temperature and elevated temperature service regarding the service conditions of materials."

(Go to : Section II Part D Sub part 1 Tables 1A and 1B)

UG-20 DESIGN TEMPERATURE (ASME VIII)

(a) Maximum.

Except as required in UW-2(d)(3), the

maximum temperature used in design shall be not less

than the mean metal temperature (through the thickness)

expected under operating conditions for the part considered

(see 3-2). If necessary, the metal temperature shall be determined

by computation or by measurement from equipment

in service under equivalent operating conditions.

(b) Minimum.

The minimum metal temperature used in

design shall be the lowest expected in service except when

lower temperatures are permitted by the rules of this Division

(see UCS-66, UCS-160, and footnote 37, UG-116).

The minimum mean metal temperature shall be determined

by the principles described in (a) above. Consideration

15

shall include the lowest operating temperature, operational

upsets, autorefrigeration, atmospheric temperature, and any

other sources of cooling [except as permitted in (f)(3)

below for vessels meeting the requirements of (f) below].

The MDMT marked on the nameplate shall correspond to

a coincident pressure equal to the MAWP. When there

are multiple MAWP's, the largest value shall be used to

establish the MDMT marked on the nameplate. Additional

MDMT's corresponding with other MAWP's may also be

marked on the nameplate (see footnote 37).

(c)

Design temperatures that exceed the temperature

limit in the applicability column shown in Section II, Part

D, Subpart 1, Tables 1A, 1B, and 3 are not permitted. In

addition, design temperatures for vessels under external

pressure shall not exceed the maximum temperatures given

on the external pressure charts.

(d)

The design of zones with different metal temperatures

may be based on their determined temperatures.

(e)

Suggested methods for obtaining the operating temperature

of vessel walls in service are given in Appendix C.

(f)

Impact testing per UG-84 is not mandatory for pressure

vessel materials that satisfy all of the following:

(1)

The material shall be limited to P-No. 1, Gr. No.

1 or 2, and the thickness, as defined in UCS-66(a) [see

also Note (1) in Fig. UCS-66.2], shall not exceed that given

in (a) or (b) below:

(a)

1⁄2 in. (13 mm) for materials listed in Curve A

of Fig. UCS-66;

(b)

1 in. (25 mm) for materials listed in Curve B,

C, or D of Fig. UCS-66.

(2)

The completed vessel shall be hydrostatically

tested per UG-99(b) or (c) or 27-4.

(3)

Design temperature is no warmer than 650°F

(345°C) nor colder than −20°F (−29°C). Occasional

operating temperatures colder than −20°F (−29°C) are

acceptable when due to lower seasonal atmospheric temperature.

(4)

The thermal or mechanical shock loadings are not

a controlling design requirement. (See UG-22.)

(5)

Cyclical loading is not a controlling design

requirement. (See UG-22)

Spot on again!!!

Thankyou verymuch Sir.