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Jiaxing zhapu hangwan heavy machinery co. ,ltd

 

 

 

 

 

 

 

 

Standard of stainless steel fracturing pump forging

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Released on April 20, 2017                                                           Implemented on Oct 1, 2017


Standard of stainless steel fracturing pump forging

 

Introduction

 

The storage energy, oil and gas on the earth are unrenewable and precious resource. With the deepening of human dependence on oil and gas resources, this resource becomes more and more important. It determines a country's development and strength. At the time of the rapid development of the global economy, oil and gas production is increasing. At the same time, the yield rate per unit of oil and gas well is an important issue in oil and gas industry. By optimizing or improving the production process and equipment, we can increase the output per unit of oil and gas well, reduce production cost and improve economic benefits.

"Fracturing pump" is one of the main equipment in oil and gas production equipment. With the continuous development of science and technology, the fracturing technology has also been unprecedentedly developed. For decades, the research and development of "fracturing pump" has never stopped, especially in recent years, with the constant improvement of fracturing technology, the pressure capacity and service life of "fracturing pump" have been put forward with higher requirements. The "fracturing pump" made of the original low-alloy steel is used under the requirements of the new fracturing technology. Not only is the pressure capacity insufficient, but also the service life is particularly short, and the shortest time with pressure is less than 100 hours. This highlights how inefficient work is, and the economic benefits will be greatly affected.

In view of the above situation, our company has established a research and development team since April 2013. After more than three years, we analyzed the working principle of "pressure pump" by the investigation and inspection. The pressure, working condition, media and geological structure are studied in detail. The "fracturing pump" shall be manufactured with a high-alloy steel of high strength, high toughness and plasticity, corrosion resistance and wear resistance, which can meet the requirements of new technology. Hundreds of tests have been carried out on a variety of materials, and the results show that the materials in the framework of this standard are in full compliance with the new technology and new process conditions. In June 2016, the first stainless steel "fracturing pump" produced by our company was delivered to Chongqing Fuling rock dam shale gas production site for working condition experiment. The experimental results show that all the indexes meet the technical requirements, and the cumulative working time with pressure reaches more than 1000 hours. This pioneered the use of similar products in adverse conditions for the longest, which has been praised unanimously by the industry.

We will make persistent efforts and continue to innovate, and we will be able to develop better products to put on the market and serve the society.

  1. Scope

This standard is applicable to the production of "fracturing pump" for oil, shale oil and shale gas exploitation. This standard is not applicable to other industries.

2. Normative reference documents

If any of the following documents are dated references, the dated version is applicable to this document. For undated references, the latest version (including all amendments) applies to this document.

GB/T222       The finished chemical composition of steel allows deviation

GB/T226       Low power structure of steel and acid corrosion test for defects

GB/T228.1    Tensile tests of metallic materials - part 1: room temperature test methods 

GB/T229       Charpy pendulum impact test method for metallic materials

GB/T231.1    Brinell hardness test of metallic materials - part 1: test methods

ASTM A370  Standard test method and definition for mechanical properties test of steel products

GB/T6394     Method for the determination of metal average grain size

ASTM E112  Standard test method for the determination of average grain size

GB/T10561   Determination of nonmetallic inclusion in steel - a microscopic examination of standard rating chart

GB/T11170    Determination of stainless steel multi-element content; spark discharge atomic emission spectrometry (conventional method)

NB/T47013.5Non-destructive test of pressure-bearing equipment - part 5: penetration test

ASTM AB88/A388M   Ultrasonic inspection of large steel forging

 

33. Technical requirements

3.1 Smelting method

This standard uses VODC,  with full vacuum smelting, fine grain pure killed steel, or arc furnace smelting +AOD vacuum refining. If necessary, electro-slag remelting or other smelting methods of higher quality can be used.

3.2 Forging

3.2.1 Steel shall be used for the forging of the pump head, and the T end and B end of the steel ingot (water gap, riser) shall have enough cutting allowance to ensure that the forging is free of shrinkage hole and severe segregation.

3.2.2 The forging equipment shall have sufficient power and adopt the three-dimensional forging method, so that the entire section of the forging can be fully forged. The total forging ratio is greater than 5, and the upsetting ratio is greater than 3.

3.2.3 The temperature of first and last forging shall be strictly controlled by heating evenly into the furnace with steel for forging. Thermal insulation should be sufficient to prevent the impact of Yin and Yang fire or overheat on forging quality.

3.2.4 Post-forging heat treatment: after forging, it shall be conducted in a special heat treatment furnace for heat treatment, which requires N+T (normalizing + temper).

3.3 Chemical composition:

3.3.1 The component of forging shall comply with table 1

                          Table 1 Chemical composition(%)

C

Mn

Si

S

P

Ni

Cr

≤0.080

≤2.0

≤1.0

≤0.015

≤0.020

3.0-7.0

11.5-18.0

Mo

Cu

Nb

V

H

0

N

≤2.0

≤4.50

≤0.50

≤0.20

≤2PPM

≤20PPM

≤80PPM

Note: H, O and N are not used as assessment indicators, and data are provided by the manufacturer. The chemical composition shall be adjusted by the manufacturer according to the mechanical property requirements in 10.4[table 3].

3.4 Non-metallic inclusions are evaluated according to the ASTM standard rating chart in GB/T10561, which conforms to the requirements in table 2.

 

Table 2 Non-metallic inclusion

Type

A

B

C

D

DS

Total

Coarse

1 grade

1 grade

1 grade

1.5 grade

1 grade

2.5 grade

Fine 

1 grade

1 grade

1 grade

1.5 grade

1 grade

2.5 grade

3.5 Blank test

3.5.1 Defects such as cracks and folding on the surface of forgings which affect the machining dimension are not allowed. If defects are present but do not affect finishing, they may be removed by cold cutting. Defects are not allowed to be removed by flame or other oxidization. Osmotic test shall be conducted after the defect is cleared to confirm that the defect has been completely removed.

3.5.2 Repair welding is not allowed in any part of the forging. All acts of fire (except heat treatment) are prohibited.

3.6 Rough machining

3.6.1 Rough machining of forgings shall be carried out according to rough machining drawing and process. Surface roughness Ra 6.3 after rough machining.

3.6.2 Hazardous defects such as cracks, bubbles, scarring, folding, slag inclusion, and porosity are not allowed on the surface of forgings after rough machining.

3.7 Non-destructive testing

3.7.1 Ultrasonic inspection: 100% ultrasonic flaw detection shall be performed after the rough machining of the forgings are exposed to light. The flaw detection method is in accordance with “ASTM A388/A388M ultrasonic inspection standard for large steel forgings”.

3.7.2 Defects such as cracks, white spots, shrinkage holes and folding are not allowed in the flaw detection of forgings.

3.7.3 A single defect of equivalent diameter greater than Φ2 shall not be allowed in the forgings. Density area defects are not allowed (defects of equivalent diameter≤Φ1.6 shall be excluded, but clutter height caused by defects shall be less than 50% of the magnitude of equivalent diameter Φ1.6). 

3.7.4 Decrease of bottom wave caused by defects is ≤6dB

3.7.5 Floating signal and strip defect signal are not allowed.

3.7.6 Penetration testing: conducted in accordance with “NB/T47013.4 non-destructive testing of pressure-bearing equipment part 5: penetration testing”.

37.6.1 After final machining of the pump head body, the inner cavity shall be tested by 100% infiltration. No linear or circular defects are allowed in the intersecting line. The cumulative length of linear or circular defects within the range of 100*100mm in the non-intersecting line of the inner cavity shall not exceed 3mm, and no chain distribution is allowed. The inner cavity defects are allowed to be polished off, and the stress distribution in the cavity of the pump head cannot be significantly changed after removal of the defects, and local eddy current cannot be formed.

3.7.6.2 Defects of any direction length or depth greater than 3mm are not allowed on the external surface of the pump head body after finishing. Defect display in the range of 100*100mm shall not exceed 5mm and shall not be chain distributed.

3.8 Performance heat treatment:

3.8 Performance heat treatment (Q+T) shall be conducted after the forging is finished roughly and qualified through non-destructive testing. The heat treatment process is determined by the manufacturer according to the performance requirements, chemical composition, equipment condition, cooling method, cooling medium and other factors, with the purpose of meeting the performance requirements.

3.9 Mechanical properties

3.9.1 Mechanical properties test shall be conducted after heat treatment of forging performance.

3.9.2 Sampling method: the sample shall be taken from a place 50mm away from the surface of the forging body (according to the sampling diagram), and shall be divided into longitudinal and transverse groups. One pull and three punches shall be made for each group of sample.

3.9.3 Test method: according to GB/T228, GB/T229 or ASTM A370.

3.10 Mechanical properties

3.10.1 Mechanical properties of the forgings shall comply with the provisions in table 3

 

Table 3 Mechanical properties

Sample direction

σS

σb

δ4%

ψ%

AkV/J-30℃

Longitudinal

≤830

960-1150

16

55

≤70

Transverse

≤810

940-1130

16

50

≤70

Note: one sample test value is allowed to be lower than the standard value in each group of test, and shall not be lower than 80% of the standard value, but the average value of three samples in one group of test shall meet the standard requirements.

3.10.2 Retest: if one test is unqualified, double samples can be taken from adjacent places of the original sampling site for retest. If not qualified, reheat treatment is allowed.

3.10.3 Reheat treatment: reheat treatment is allowed when the mechanical property test of the forging fails, and the heat treatment times of the forging shall not exceed three times. The tempering times are not counted.

3.11 Low power structure test:

3.11.1 the low power structure level of acid leaching should meet the requirements of group 1 in “GB/ T1220-2007”. Ultrasound flaw detection is allowed to replace low power structure examination. Low power structure requirements shall comply with table 4.

 

Table 4

Group

Central porosity

General porosity

Ingot segregation

General spot segregation

Edge spot segregation

Rim hole

Intergranular crack

Scale

≤1.5

≤1.5

≤1.5

≤1.5

Not allowed

Not allowed

Not allowed

3.12 Grain size:

3.12.1 Evaluation method of grain size: according to GB/T6394 or ASTM E112.

3.12.2 Grain size requirements: the average grain size after the final heat treatment of the forging shall be class 5 or more. The grain size shall not be acceptance condition, but the manufacturer shall provide the test report of grain size.

3.13 Logo:

3.13.1 After finishing the forging and passing the inspection, the smelting furnace number, material, number, part number and production date in the production process shall be printed on the specified area with low stress steel.

3.14 Delivery of forgings shall be accompanied by a certificate of quality which shall include:

 

3.14.1 Relevant reports (original material warranty, re-inspection report of chemical composition, flaw detection report, penetration test report, non-metallic inclusion test report, low-power test report, mechanical property report, grain size report, heat treatment status indicated) shall be provided upon delivery of forgings.

 

4. This standard is the enterprise standard of the company, and has nothing to do with other standards.

5. This standard interpretation belongs to the drafter.

6. Drafter of this standard: Jiaxing zhapu hangwan heavy machinery co.,ltd.

 

April 20, 2017

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