What is Reinforcing Steel Bars or Rebars?

Reinforced steel bars or Rebars are used to help concrete withstand tension forces. Concrete by nature is sufficiently strong to compression forces, however the tension forces can crack concrete. Therefore with the combination of reinforced steel bar and its concrete strength and texture, it can make the main structure withstand the tension forces hence strengthening the buildings. The deformed pattern on a rebar will help the concrete to adhere to the reinforcing steel surface at even greater level. It's widely available in different form. 

Deformed Bars

Deformed bars are used to reinforce high strength concrete because of their high strength and their ability to hold on to the cement. The deformed bars are made in accordance with TIS24-2548 (2005) SD30, SD40, SD50 from 6-40mm at 10 and 12m long.

Round Bars

Round bars are suitable for using as reinforced bars for small and medium building such as commercial buildings and houses. The round bars are made to the TIS20-2543 with standard size 6-34mm at 10 and 12m long.

How to select the good quality reinforced steel bars

Steel Skin

1. Round bars: the skin should be smooth with round diameter 
2. Deformed bars: the pitch should be equal across the bar

Size and correct diameter and more importantly the weight that matches with the specification 

1. The bar should have ability to bend without jeopardizing the bars
2. The rust on the skin is rather common in SEA where atmosphere is humid and hot, however there shouldn't be the rust deep down inside the bars 

TIS standard

Each bar is inspected for its chemical structure and passed through many mechanical tests ranging from tensile to cold bend testing. Our products are conformed to TIS Standard 20-2543 and 24-2548. We can guarantee to maintain consistent quality production and distribution in the following products: 

1. Round Bar (Grade SR24): 6, 9, 12, 15, 19, and 25mm. TIS 20-2543
2. Deformed Bar (Grade SD30, SD40, and SD50) : 10, 12, 16, 20, 25, 28, 32, and 40mm. TIS 20-2548
3. Square Bar : 12, 16, 19mm.

Production Process

Steel bars in Thailand are mostly produced with industrial standard production process called Electric Arc Furnace or EAF. Production of re-bars begins with charging reight porportion of steel scrps, high quality lime and coke into and Electric Arch Furnace or EAF. The mixures are melted by energy generated by electric arc. During melting process, the steel undergoes complex chemical and physical processes. When temperature and chemical compositions are correct and verified by laboratory test, the molten steel is tapped into a ladle and sent to the continuous caster where high quality billets are produced. The quality billets are later reheated to 1050 degrees celcius prior to being rolled to the desired size and quality. The products which can be produced through this process are deformed bars SD 30, SD 40, and SD 50 accordance to TIS 24-2548 (2005) from 6-40mm and round bars SR24 in according to TIS 20-2543 (2000) from 6-34mm diameter.

Metallurgy of Steel

Steel can be broadly classed into two categories, namely plain carbon steel and alloy steel. The steel produced in Thailand falls into first group having derived its properties from three main elements: Carbon; Silicon; and Manganese. The local streel can be further divided to those with carbon less than 0.25% and those with carbon between 0.25-0.35%. The former are used mainly to make wire rods and round bars while the latter are for high strength deformed bars.

Properties and Application of Plain Carbon Steel 

To achieve highest quality to satisfy the needs of our customers, the properties and application of plain carbon steel from our factory depends mostly on:

1. Content and content ratio of Carbon, Silicon, and Manganese. Increasing the carbon content has strong positive effects on hardness and stength while enongation is sharply reduced. Silicon increases both yield strength and tensile strength but decreases elongation. Manganese increases hardening and tensile strength but does not adversely affec tht elongation strongly. Control of the content of these three main elements and trace elements such as Sulfur, Phosphorous, Copper, Tin are keys to steel performance.
2. Process control during melting and casting to ensure steel cleanliness and properly developed microstructure.
3. Process control during rolling and modern rolling equipments. The BISW is proud of our state of art rolling facilities. Main features of the rolling mills are computer controlled H-V rolling strands and a temperature monitoring and control system. 

TIS Standard Certificate