API 650 IMPACT TEST REQUIREMENT.

[manoj john]

Dear All,

Can anyone give information for the impact test requirement as per API 650 for carbon steel plate thickness for atmospheric storage tank.

Thanks & Regards.

Manoj 

[narasimha murthy]

 

As per API 650

2.2.1.4

Shell plates are limited to a maximum thickness of

45 mm (1.75 in.) unless a lesser thickness is stated in this

standard or in the plate specification. Plates used as inserts or

flanges may be thicker than 45 mm (1.75 in.). Plates thicker

than 40 mm (1.5 in.) shall be normalized or quench tempered,

killed, made to fine-grain practice, and impact tested.

Regards,

 

J.N.Murthy

 

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[Vino Varghese]

Dear Sir,

 

I was in an impression that the impact requirement is governed by Temperature, like - 29 Degree C below... but how does thickness affects the Impact Test?

 

Can you please through more light for the requirement of Impact Test based on thickness criteria?

 

Thanks & Regards

Vino-Doha

[narasimha murthy]

Dear Mr.Vino,

 

The requirement of Mr.Manoj john was related with the API 650 Tanks, offcourse temperature of -29 Deg Cent shall be considered and is very important for piping / Pipe line also.

 

Please refer to the fig: 2-1—Minimum Permissible Design Metal Temperature for Materials Used in Tank Shells

Without Impact Testing

Regards,

[Ajithkumar]

Dear Mr. Vino,

 

Please look into the following requirements also.

 

7.2.2 Impact Tests

7.2.2.1 Impact tests for the qualification of welding procedures

shall comply with the applicable provisions of 2.2.8

and shall be made at or below the design metal temperature.

7.2.2.2 When impact testing of a material is required by

2.2.8, 2.2.9, or 2.5.5, impact tests of the heat-affected zone

shall be made for all automatic and semiautomatic welding

procedures.

7.2.2.3 For all materials to be used at a design metal temperature

below 10°C (50°F), the qualification of the welding

procedure for vertical joints shall include impact tests of the

weld metal. If vertical joints are to be made by an automatic

or semiautomatic process, impact tests of the heat-affected

zone shall also be made.

7.2.2.4 When the design metal temperature is below –7°C

(20°F), impact tests of the weld metal shall be made for all

procedures used for welding the components listed in 2.2.9.1,

for welding attachments to these components, and for fabricating

shell nozzles and manholes from pipe and forgings

listed in 2.5.

7.2.2.5 Impact tests shall show minimum values for acceptance

in accordance with 2.2.8.3 and the following:

a. For P1, Group 1, materials—20 J (15 ft-lbf), average of

three specimens.

b. For P1, Group 2, materials—27 J (20 ft-lbf), average of

three specimens.

c. For P1, Group 3, materials—34 J (25 ft-lbf), average of

three specimens.

For shell plates thicker than 40 mm (11/2 in.), these values

shall be increased by 7 J (5 ft-lbf) for each 12.5 mm (1/2 in.)

over 40 mm (11/2 in.). Interpolation is permitted.

 

Thanks & Regards,

Ajithkumar. K       

[Shaik Basha]

Dear Ajith,

thanks for your precious information. Could you advise from what thickness we shall consider the impact testing. our tank first shell course is 20mm and MDMT is -7 degree centigrade. is it from 13MM applicable or all thickness.

Appreciate your response.