How to implement the quality control in the construction of steel structure engineering production and installation unit is mainly through the full-time and part-time personnel with quality control function of relevant departments to perform their own responsibilities in the quality control.The quality control method is mainly through the preparation and audit of relevant technical documents and reports, through on-site process inspection and final inspection and necessary tests.

1、 Prepare and review relevant technical documents and reports

The preparation and review of technical quality documents and reports is an important means for comprehensive control of project quality. The specific contents are as follows:

1.Production project

(1) Review construction drawings, design changes and modification drawings.

(2) Test and compile the technical appraisal certificate of new technology, new material and new structure.

(3) Prepare and review technical process documents (such as manufacturing essentials, technical instructions, painting essentials, packaging and transportation essentials, process procedures), etc., and quality inspection documents (such as quality inspection essentials, quality inspection form, etc.).

(4) Quality inspection form for relevant materials and semi-finished products.

(5) Timely feedback the statistical data or management chart reflecting the dynamic process quality.

(6) Timely deal with the quality accidents of relevant engineering projects, make treatment reports, and put forward appropriate corrective and preventive measures. 

(7) Do a good job in product acceptance and delivery data.

2.Installation items

(1) Prepare and review the construction scheme and construction organization design to ensure the project quality with reliable technical measures.

(2) Review the formal commencement report and issue the commencement instruction.

(3) Review the technical qualification certificate and personnel qualification certificate of each Subcontractor entering the construction site.

(4) Review the quality inspection guide, material certificate and test report of relevant materials, finished products and semi-finished products.

(5) Review construction drawings, design changes, modification drawings and notices, agreements and instructions.

(6) Prepare the technical appraisal of new process, new technology, new material and new structure related to the test.

(7) Make process handover inspection and quality inspection report of subdivisional and divisional works.

(8) Deal with the quality accident in time, make the treatment report, and put forward the appropriate corrective and preventive measures.

(9) Timely feedback process quality dynamic statistical data or management chart.

(10) Timely complete the project acceptance data.

2、 Process inspection and final inspection

1.Inspection contents

(1) Material preparation inspection.Whether the appearance and size of the products provided by customers meet the technical quality standards for the purchased materials and steel components entering the site, and whether the machine tool rollers are in good working condition.

(2) Inspection before construction.Whether the site has the starting conditions and whether the project quality can be guaranteed after the commencement.

(3) Process handover inspection.On the basis of self inspection and mutual inspection, quality inspection personnel inspection and process handover inspection should be strengthened for important processes or processes with significant impact on project quality.

(4) Inspection of concealed works.All concealed works can only be covered up after being certified by quality inspection personnel.The work on the installation site must be certified by the customer supervision.

(5) Follow up, supervise and inspect.Follow up supervision and inspection shall be carried out for engineering structures with great difficulty in construction or construction with special requirements and easy to produce quality problems.

(6) After the completion of subdivisional and divisional works, the acceptance record shall be signed after self inspection and approval by the supervisor.

2.Methods of inspection

The inspection method is divided into on-site quality inspection and test inspection

(1) On site quality inspection methods include visual inspection method and actual measurement method

a. Visual inspection

The means of visual inspection can be summed up as four words: look, touch, knock and photograph.

[look] is to visually inspect the appearance according to the quality standard.For example, the appearance of steel should be free of cracks, scabs, folds, hemp lines, bubbles and inclusions; the construction process should be carried out in a reasonable construction sequence, the workers’ operation is normal, and the instrument indication is correct; the weld surface quality should be free of cracks, weld beading, spatter, undercut, slag inclusion, air hole, poor joint, etc., which should meet the relevant provisions of the code for construction and acceptance。

The quality of coating construction should be derusting to the level specified in the design and contract. No rain should be allowed 4 hours after coating. The surface of paint film should be uniform, meticulous, without obvious color difference, sagging, tarnish, wrinkling, pinhole, bubble, shedding, dirt adhesion, missed coating, etc.

Touch is a feeling check.It is mainly applicable to the internal corners of steel structure engineers, such as the smoothness of the corner cutting of stiffening plate of steel components and the welding cladding angle can be identified by hand.

[knock] is to check the sound sense with tools.For example, if the steel structure engineering column angle pad is padded firmly, and the high-strength screw inspection joint is close and tight, the knocking inspection can be used to determine whether it is close to the actual or not through the sound.

For parts that are difficult to see or have dark light, the method of mirror reflection or light illumination can be used for inspection.

B it’s impossible

The actual measurement inspection method is to judge whether the quality is qualified by comparing the measured data with the allowable deviation specified in the construction specifications and evaluation standards. The means of the actual measurement inspection method can be summarized into four words: measurement, pulling, measuring and plugging.

[measurement] is to check the manufacturing accuracy with steel tape, steel ruler, angle ruler, vernier caliper and weld inspection ruler, measure the installation deviation, and measure the weld appearance size.

The method of pulling and twisting is to check the component.

[measurement] is to detect the deviation of axis, elevation, perpendicularity, internal quality of weld, temperature and humidity with measuring tools and measuring instruments.

[plug] is to check with feeler gauge, hole tester and arc-shaped mould.If a feeler gauge is used to check the contact surface clearance of high-strength bolts, the hole passing rate is checked with a hole tester, and the grid steel ball is checked with arc-shaped sleeve die.

(2) Test and inspection

Test inspection refers to the inspection method which can judge the quality only by means of test.Such as mechanical property test and chemical analysis, welding procedure qualification test, welding towing test plate test, high strength bolt connection pair test, anti sliding coefficient test of friction surface, etc.

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