AVB’s Steel Wire Rod Production
‘Aço Verde do Brasil’ has started wire rod manufacturing on early 2018. The process has been developed via LD Steel Shop and from a double-line hot rolling mill. Raw material used in the AVB process is the liquid pig iron resulting from iron ore purchased from VALE, and the company’s own wood charcoal production. AVB’s biggest differential is steel production using LD Steel Shop, a process that is very important for the SAE 1006 steel market, applied for drawing wire gauges below 2.00 mm, a well-representative product in the Brazilian market.
Applications and usages…
By having a well-established raw material structure and with state-of-the-art and high-technology equipment, AVB produces several types of low-, medium-, and high-content carbon, being present in several segments, such as: civil construction, industry, agricultural and cattle raising, and automotive sectors. Wire rod is manufactured in coils with several gauges, ranging from 5.5 mm to 16 mm.
The AVB Wide Rod is used in the manufacture of fastening products, such as nails, wires for steel wool, fasteners, MIG welding and electrodes, nuts, bolts and rivets. It is also used in the production of coil springs and bearing balls.
Wire rods are also used for applications in the sectors of farming, civil construction, electrification, cables, household appliances (white line), bars for mechanical construction, shock absorber shafts, and many others.
Specification for Steel Wire Rods
To set out the minimum quality requirements for wire rod produced from AVB’s LD melt shop billets.
2. CHEMICAL COMPOSITION:
The chemical compositions of the steels intended for the production of wire rods were established based on the SAE, J403 and J404 standards, and represented by Table 1 below:
3. DIMENSIONAL REQUIREMENTS
The dimensional requirements and tolerances were established based on the level of quality required by the laminated wire rod. Table 2 presents the variations permitted according to the laminated gauge and the level of quality required.
4. SURFACE CONDITIONS
The wire rod, on its surface, must be free of defects that might hinder the application of the product; however, surface defects with a maximum depth presented in Table 3 will be permitted.
For a quality requirement higher than the one mentioned above, the technical department should be consulted. For steel grades with carbon content above 1012C, the wire rod must be free of total decarburization; in the case of partial decarburization, it must not exceed the numbers set out in Table 4.
5. INNER SOUNDNESS
It must be guaranteed that every wire rod is free of gaps, shrinkages, porosity and cracks in the center.
The inner quality requirements were established based on the level of quality required by the laminated wire rod. Table 5 presents the variations permitted according to the level of quality required.
Note: The requirement for grain size applies only to steels with a carbon content above 0.20%.
6. MECHANICAL PROPERTIES
The mechanical property of the wire rod should be controlled through a traction testing, where the limit values for traction resistance, elongation and reduction of area should be aimed according to Table 7. In case the value found falls outside the range specified in Table 6, further testing must be carried out (retest, chemical analysis and micrography, the last two of which are optional).
After the compaction of the roll, the wire rod must meet the requirements shown in Table 7; weights that do not meet the ones shown can be provided upon consultation.
The compaction of the rolls must not cause surface damages to the material spirals and the minimum stacking of 4 levels must be ensured, without damaging the material or causing the loosening of the braces.
The label used for identification of the roll must have sufficient mechanical resistance in order to avoid manual “picking”; it must be weatherproof and resistant to acid baths (HCl and H2SO4), without any failure in the information contained on the label.
Figure 1 shows the model and information that must be included on each identification label of the wire rod roll.
Every wire rod roll must have 2 identification labels, located in the inner part of the roll at opposite ends and different braces, as shown in Figure 2.