4.5 Calculation of the required minimum component wall thickness for the parameters of further service

The calculation of the minimum component wall thickness for the parameters of further service goe was made based on the following formula:

$$\mathbf{g}\_{\alpha\epsilon} = \frac{\left(p\_{cp} \cdot D\_x\right)}{\left[\left(2k - p\_{cp}\right) \cdot z + 2p\_{cp}\right]}$$

where goe is the minimum component wall thickness for the parameters of further service, pep is the operating pressure of further service, DOut is the nominal outside diameter, k is the acceptable stress, and z is the weakening coefficient.


#### Table 5.

Parameters of further service and geometrical dimensions of test pipeline elbow made of 14MoV6 steel after 200,000 h service.

The values obtained for pressure po and pep and for the adopted different times tep and temperature levels of further service Tep for the material of test primary

Comparison of the required minimum pipeline elbow wall thickness goe for the adopted parameters of further service (pep,Tep) to the minimum actual wall thickness gact min measured on the component for the adopted

Temperature of further service Tep = 540°C Time of further service tep, h 30,000 50,000 100,000 Operating pressure of further service pep, MPa Required minimum wall thickness goe, mm 14.2 29.38 31.64 37.40 13.8 28.62 30.84 36.47

The Procedure for Determining the Time of Safe Service beyond the Design Service Time Based…

Required minimum wall thickness of primary steam pipeline elbow made of 14MoV6–3 steel for the adopted

Table 6.

Figure 14.

65

temperature of further service Tep = 540°C.

parameters of further service.

DOI: http://dx.doi.org/10.5772/intechopen.84986

steam pipeline elbow made of 13HMF steel are summarised in Table 6.

The Procedure for Determining the Time of Safe Service beyond the Design Service Time Based… DOI: http://dx.doi.org/10.5772/intechopen.84986


Table 6.

4.4 Definition of parameters of further service

Component Adopted time of further

Creep Characteristics of Engineering Materials

Table 4.

Table 5.

64

200,000 h service.

under creep conditions

service tep, h

Elbow 10,000 84

required values are summarised in Table 5.

parameters of further service

The parameters of further service are defined to be the same as the previous ones. To calculate the required minimum wall thickness, in addition to pressure pep and temperature Tep of the component, it is also necessary to define its nominal outside diameter DOut, nominal wall thickness gn, design pressure po, operating pressure of further service pe, and construction weakening coefficient z. The

30,000 71.2 50,000 65.6 100,000 54.4

Determined values of acceptable stress k for the adopted levels of temperature Tep and times te of further service for the material of test primary steam pipeline component made of 14MoV6–3 steel after 200,000 h service

4.5 Calculation of the required minimum component wall thickness for the

2k � pep � �

where goe is the minimum component wall thickness for the parameters of further service, pep is the operating pressure of further service, DOut is the nominal outside diameter, k is the acceptable stress, and z is the weakening coefficient.

No. Parameter Unit Value Nominal outside diameter DOut mm 324 Nominal wall thickness gn mm 40 Minimum actual wall thickness gact min mm 36.8 Time of further service tep h 30,000

 Temperature of further service Tep °C 540 Design pressure po MPa 14.2 Operating pressure of further service pep MPa 13.8 Weakening coefficient z — 1

Parameters of further service and geometrical dimensions of test pipeline elbow made of 14MoV6 steel after

further service goe was made based on the following formula:

goe ¼

The calculation of the minimum component wall thickness for the parameters of

pep � Dz � �

h i

� z þ 2pep

50,000 100,000

Acceptable stress k, MPa for temperature of further service Tep = 540°C

> Required minimum wall thickness of primary steam pipeline elbow made of 14MoV6–3 steel for the adopted parameters of further service.

#### Figure 14.

Comparison of the required minimum pipeline elbow wall thickness goe for the adopted parameters of further service (pep,Tep) to the minimum actual wall thickness gact min measured on the component for the adopted temperature of further service Tep = 540°C.

The values obtained for pressure po and pep and for the adopted different times tep and temperature levels of further service Tep for the material of test primary steam pipeline elbow made of 13HMF steel are summarised in Table 6.
