Quality control is not a step of the process but a system from the very beginning of raw materials quality control to the end final review.

Following are details for each process of our control system:

4.1 Raw Materials Quality Control

1. Chemical Analysis:

Testing: Raw materials are tested for their chemical composition to ensure they meet the required specifications. This includes analyzing the content of iron ore, scrap steel, and alloying elements.

Adjustments: If necessary, adjustments are made to the mix of raw materials to achieve the desired composition and properties of the steel.

2. Physical Properties Testing:

Ore and Scrap: Testing for physical properties such as size distribution, density, and hardness is important for efficient processing.

Fluxes: Ensure that fluxes have the correct properties for effective impurity removal.

4.2 Heating process control

Inspection: Before and after heating, billets are inspected for any signs of defects or irregularities. Quality control ensures that only billets meeting the necessary standards proceed to the rolling stage.

Adjustments: If any issues are detected, adjustments to the heating process or billet handling might be made to correct the problem.

4.3 Cutting quality control

Length Verification: After cutting, the lengths of the rebars are checked using measuring tools to ensure they meet the specified dimensions.

Edge Inspection: The cut ends are inspected for sharpness and any signs of deformation or irregularity that could affect handling or installation.

4.4 Bending quality control

Shape and Dimensions: After bending, the rebars are checked to ensure they conform to the required shapes and dimensions. This includes verifying the angles and radii of the bends.

Visual Inspection: Inspect for any visible defects such as cracks or kinks that could compromise the integrity of the rebars.

After all the above quality control we still need to do the inspection and test.

Inspection and Testing

Inspection and testing are crucial in the fabrication of steel bars (rebars) to ensure they meet the required standards and are suitable for use in construction. Here’s a detailed overview of the key inspection and testing processes involved:

1. Visual Inspection

Surface Quality: Inspect the surface of the steel bars for visible defects such as cracks, rust, or significant irregularities. Surface defects can affect the performance and bonding of the bars in concrete.

Dimensional Checks: Verify that the diameter and length of the bars conform to the specified tolerances. This is typically done using measuring tools like calipers and rulers.

Deformations: Check the surface deformations (e.g., ridges or patterns) to ensure they are consistent with the required specifications and are uniformly distributed.

2. Mechanical Testing

Tensile Test: This test measures the tensile strength, yield strength, and elongation of the steel bars. A sample bar is pulled to failure in a tensile testing machine, and the stress-strain curve is analyzed to determine its mechanical properties.

Yield Strength: Determines the stress at which the steel begins to deform plastically. This is crucial for understanding the bar’s ability to withstand loads without permanent deformation.

Ultimate Tensile Strength: Measures the maximum stress the bar can withstand before breaking.

Elongation Test: Assesses how much the steel can stretch before breaking, indicating its ductility.

3. Chemical Analysis

Composition Check: Analyze the chemical composition of the steel to ensure it meets the required specifications. This typically involves techniques like spectroscopy to measure the levels of elements such as carbon, manganese, sulfur, phosphorus, and alloying elements.

Consistency: Ensure that the chemical composition is consistent with the standards and does not deviate beyond acceptable limits, as this affects the mechanical properties and performance of the steel bars.

4. Hardness Testing

Hardness Test: Measures the resistance of the steel to deformation. Common methods include the Rockwell, Brinell, or Vickers hardness tests. The hardness value can give an indication of the steel’s ability to withstand wear and mechanical stress.

5. Non-Destructive Testing (NDT)

Ultrasonic Testing: Uses high-frequency sound waves to detect internal defects or discontinuities in the steel bars. This test helps identify issues such as voids, inclusions, or other internal flaws that may not be visible on the surface.

Magnetic Particle Inspection: For detecting surface and near-surface defects, particularly useful in detecting cracks. The steel bars are magnetized, and iron particles are applied to reveal any discontinuities.

Dye Penetrant Testing: Involves applying a dye to the surface of the bars and then a developer to reveal surface cracks and other defects.

6. Dimensional and Weight Checks

Diameter and Length: Verify that the dimensions of the steel bars are within the specified tolerances. This ensures that the bars fit correctly in their intended applications.

Weight: Check the weight of the bars to ensure consistency with the specified weight per unit length. This is important for verifying that the bars meet the required standards and are not under or overweight.