Specifications: diameter: 320 to 127 mm thickness: 0.4 to 12.7 mm Length: 6 m above, and, in accordance with customer demand, supply and other specifications of steel pipe

Steel pipe inspection content and procedures

Steel pipe inspection content and steel pipe inspection procedures


Keywords: steel pipe the test content steel pipe inspection procedures

, Pipe inspection content. Role of the examination table: finished the examination table, symmetric products steel pipes to be carried out by branch diameter, wall thickness measurement,


carbon steel pipe

A steel pipe inspection content

Check Desk role:

Finished the examination table, the the symmetrical products steel pipes to be gradually branch diameter, wall thickness measurement, quality inspection of the inside and outside surfaces at the same time.

2 size deviation calculation method;

1) the diameter deviation calculated;

Positive deviation = (D large-D male) / public × 100%


Negative deviation = (D small-D male) / D public × 100%

Diameter tolerance range = positive deviation of + negative deviation

Where: Dmax-largest steel pipe outside diameter (mm)

The Dmin-steel pipes smallest outside diameter (mm)

D - pipe Nominal Diameter (mm)

2) thickness deviation

Positive deviation (+ △ S) = × 100%

Negative deviation (- △ S) = × 100%

Wall thickness tolerance range = positive deviation + negative deviation

3) steel pipe ovality:

The ovality (p) = (D-D) / 0.5 (D + D small)] × 100%

Where: S - the largest steel pipe wall thickness (mm)

S - steel pipe minimum wall thickness (mm)

3 steel pipe and size measurement.

1) the measurement of the wall thickness and outer diameter.

(1) The diameter measurement method is:

Pipe diameter (measured in symmetrical and not less than 4:00) as unqualified products if little more than the outer diameter of the positive and negative deviation measured with calipers.

(2) wall thickness measurement method is:

Micrometer symmetrical measuring more than 8:00 in the same cross-section of the steel pipe wall thickness more than the wall thickness of the positive and negative and positive and negative deviations, if a little wall thickness more than that as unqualified products.

(3) measurement of the bending of the steel pipe:

With flat feet and a feeler gauge to measure the steel pipe bending, steel tube bending degrees greater than the value of the curvature, as unqualified.

Play tolerance provisions stipulated in the international value:

Wall thickness: ≤ 15mm 1.5mm / m

> 15 ~ 30mm 2.0mm / m

4 steel internal and external quality check

1) Check the way:

The steel pipe inner and outer surface quality inspection with the naked eye to determine.

2) the defect type:

Common defects: of the outer surface of the outer folding, hairline, scars, scratches, outer spiral, crack, separation, pockmarked face, pits, straightening and concave.

The inner surface of the common defects: centering fold within the fold, within the rolling scar within spiral.

3) the defect characteristics and the method of determining

Hairline (1)

Defect characteristics: In the steel pipe outer surface was continuous or discontinuous, the hair-like fine lines, hairline helical direction, with the perforated pipe attachments opposite direction,

Check to determine: the steel surface does not allow visible hairline, if so hairline should be clean, clear steel pipe wall thickness and outer diameter of not more than negative deviation.

(2) outside the fold:

Defect characteristics:

Presented in the steel tube outer surface of the sheet folded, some distribution law of some erratic. Outer folding spiral inwardly capillary piercing machine rotating in opposite directions, the cut pitch.

(3) Ma Face

Defect characteristics:

Steel surface rendering spiky pits.

Check to determine:

Check with the naked eye, a slight allowed to exist, validation is not allowed to exist, whether grinding ice is determined according to the defect levels, negative deviation to To repair worn steel pipe, grinding steel pipe size, and does not allow more than the wall thickness and outer diameter range.

(4) scarring

Defect characteristics:

Steel pipe internal and external surface rendering edge angular scars.

Check to determine:

With the naked eye patch steel pipe surface to allow a slight rolling scars, serious grinding, steel pipe should ensure sizes.

(5) holes (torn).

Defect characteristics:

The steel surface torn phenomenon likely local.

Check to determine:

Checked with the naked eye, the steel pipe performance is not allowed to exist torn, partially torn should be removed.

(6) within the fold

Defect characteristics:

The performance of the steel pipe inner spirally, or no rules distribution zigzag folding.

Check to determine:

Checked with the naked eye, the steel pipe inner surface is not allowed within the fold, localized within the fold should be removed no full-length folding should be sentenced to waste.

(7) Green Line

Defect characteristics:

Between the steel pipe outer surface presents a symmetrical or asymmetrical linear rolling marks, longitudinal distribution, some with a nail-shaped embossing.

Check to determine:

Visually inspect the steel tube performance allowed the blue line depth of less than 0.1 mm, its general steel pipe Please do not consider.

(8) Abrasion

Defect characteristics:

Steel pipe outer surface showed a spiral-shaped scars, and regular or irregular grooves.

Check to determine:

Visual inspection, ice Yong measurement with the amount of abrasion depth, depth of less than 0.1mm allowed other abrasions should be grinding grinding steel pipe diameter and wall thickness are not allowed to exceed the scope of the deviation.

(9) overcorrection recess

Defect characteristics:

Steel pipe internal and external surface area ranging from local depression.

Check to determine:

Visual inspection, are not allowed in the pits, the grinding steel pipe outside diameter and wall thickness should make up more than negative deviation range.

(10) ionospheric

Defect characteristics:

Appeared in the pipe ends or the inner surface of the spiral shape massive metal analysis or rupture.

Check to determine:

Visually inspect the local ionospheric should be removed, slightly layered dressing (honing)

(11) within the spiral

Defect characteristics: surface rendering spiral steel pipe bump phenomenon.

Check to determine: check with the naked eye or hand touch, spiral height should be less than 0.2mm mm. More than those sentenced to waste.

(12) a concave surface

Defect characteristics: the partial reduction of the steel surface depression, the wall voice outside the concave convex injury phenomenon.

Check to determine: the concave surface of the pipe diameter does not exceed the negative deviation allowed more than should be removed.

(13) steel pipe bending

Defect feature: steel pipe prolong degree direction is not straight. The tube ends only render the goose head bent to become the "goose head bend.

Check judgment: check with a 1.8 m square foot when the curvature exceeds the provisions of the standard brick, should be re-straightening, I can not straightening goose head bend resection.

4 tube check processing:

1) defective markers.

Requirements with Phoebe or other pen clearly marked checks knife defects.

Corresponding mark in the following form: (workshop internal regulations, look for reference only)

Steel tube defects labeled form

Hairline, outside the fold, scratch painting helix ",,,,"

Internal and external scarring, concave surface Ma zoned "circle" up "O"

The wall thickness of the end portion of ultra Poor draw "S +, S-" line

Bent tube vertical paintings ~ ~ ~ ~

Within the fold, inner spiral tube surface of the painting "x x ...

2) defects approach

(1) pass the inspection of steel pipes spray standard length measuring, weighing, strapping, warehousing.

(2) check the oil defects failed tube defect situation and then cut the head of the pipe end processing or grinding or change ruler. Need grinding or change feet hanging tube to regrinding or another day Saw the pipe that batch, class, steel, heat number, after they cut the live grinding after in hanging to re-examination of the examination table.

(3) sampling, failed Check that the mechanical properties of the steel pipe, the marked batch in the pipe, should be stored separately sent annealed, annealed steel pipe by batch re-straightening, cutting head, check.

(4) For the tomato more times and grinding or unqualified sentenced tubes and cans for the status quo, with chanting paint states, strapping, too, said storage, waiting to be processed.

Steel pipe inspection procedures

1 steel pipe schedule surface inspection regulations

1) All pipe must have smooth outer surface of compliance with the standards of plant or raw demolition requirements.

2) must be clearly marked defect marking comply with provisions in the rights Markup content.

3) It must have adequate lighting conditions, was observed by the naked eye by-branched alkaline surface, the outer surface of the existence of defects.

4) The tube must have a state can identify major defects. Prevent unqualified tube mix with the finished tube.

5) as long as it is the wall thickness irregularities within the outer diameter of the specified tolerance range, the ice does not affect the pipe according to need to use, the tube allows a slight longitudinal scars.

6) I not be lower than the minimum diameter and wall thickness deviation allows local grinding through a large grinding wheel.

7) a day succession before, all the measurement tool must be calibrated, and should be kept 0.1mm for measurement accuracy.

8) measuring the wall thickness was measured, the tool must be at right angles with the tube ends, not a measurement point on the measuring instrument can be easily in any direction flip a different angle with the rectangular, while measuring the minimum value.

By root to perform quality checks on the surface of the tube.

1) by means of various measuring instruments to measure the outer diameter of the end portion of the light pipe;

2) checking out the inner surface defects, to designate the corresponding defect marking (writing);

3) If determined not allowed the thickness deviation or with a defective pipe end with talc draw position to be pipe cutting machine for resection treatment.

Note 3 check

1) The inspector must gradually Detachment steel pipe long pass inspection, and does not allow only check both ends.

2) qualified to check the tube should be defective at different significantly (or write) cut the head of the steel pipe, must review.









API Spec 5CT


PSL1, A25 ~ X70, PSL2, B ~ X80

H40, 155, K55, N80-1 / Q, C95, C90, T grade steel, Q125, P110

The outside diameter of the tube

≤ 168.3 steel pipe tube ± 0.0075D;

> 168.3 steel pipe ± 0.0075D;

Tube roundness tolerance 0.02D, tube end roundness tolerance

D ≥ 4.5 wise and +1% D ~ -0.5% D

Spot-check frequency: at least every 100 sample a

Tube ends outside diameter

≤ 168.3-ray tube-0.4mm +1.6 mm;

> 168.3mm ± 0.0005D But the biggest steel pipe ± 16.mm;

Tube roundness tolerance 0.02D, tube end roundness tolerance 0.015D

0 - +1% D

Wall thickness tolerance

> 4 - <25mm advertising tube wall thickness +15.0% t-12.5% ​​t



The straightness deviation shall not exceed the length of the tube 0.2% L, straight pipe end each meter within local deviation should not exceed 4mm

(1) is less than 0.2% of the total length of the steel pipe

(2) in each end 1.5m length is less than 3.18mm under heavy distance (goose head bend).

Tube end within the burr

Pipe end burr should be clear and clean, sleek feel;

Burr pipe end should be clean, smooth feel;

Bevel angle

30-35 degrees; groove width of the root surface should be 1.6 ± 0.8mm

Flat end

Cut diagonally

Tube ends cut oblique should not exceed 1.6mm


Fine water pressure

P = 2st / D steel grade the size standard test pressure (%)

A no 60A

B Any 60A

X42 ~ X120 ≤ 141.3 60B

141.3-≤ 219.1 75B

> 219.1 85B

A: For D> 88.9mm test pressure can be not more than 19.0MPa

B: The test pressure can not be no more than 20.7MPA

P = (2 × f × ys × t) / D

P-hydrostatic test pressure, units of megapascals (MPa)

the specification code f-factor greater than 9.625 in. the j55, K55f to 0.6 0.8 grade and specifications

the ys - tube provisions do small yield strength MPa units

Non-destructive testing

ASTM standard E213, the tube body 100% inspection. Requires the use of a method or a variety of methods to be used in combination.

100% detection

Performance Test

Performance: two finished tube furnace batch sampling 1 group to conduct a performance test analysis. For while processing steel pipe, both had to sampling.

Performance: two finished tube furnace batch sampling 1 group to conduct a performance test analysis.

Path Check

Flowline (TFL tube) should pass through the check out by the root

Path checks should be out by the root

The quality and appearance of other defects

Inner and outer surface shall not have cracks, folded, rolled fold (within the fold, outside the fold), separation, scarring, these defects should be completely clear, its clear at the smooth transition, without hard edges, wall thickness is not clear at the actual the minimum required on the pipe wall thickness

≥ 0.3mm pit, pockmarked face grinding.

Inner and outer surface shall not have cracks, folded, rolled fold (within the fold, outside the fold), separation, scarring, these defects should be completely clear at the actual wall thickness of not less than the minimum wall thickness of steel pipe provisions

≥ 0.3mm pit, pockmarked face grinding

Remanence measurement requirements

Average before Gauss meter with a Hall effect measurement, along the circumferential direction of approximately 90 ° C, at least read the four readings should not exceed 30 Gauss, cut either a reading should not be higher than 35 gauss.


Visual inspection illumination requirements

Check the surface of ambient light should not be lower than 300Lux

The check surface ambient light should not be less than 500 Lux


Meters weight (Kg / M): W = 0.02466 (Dt) t (D: outer diameter; t: wall thickness)

Single +10% -3.5%

Single: +6.5% to -3.5%

Weight: W = 0.0246615 (D-t) t

Steel pipe inspection content and steel pipe inspection procedures.


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