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How to remove impurities from Hi-tensile scaffolding?

August 17, 2021

What is the difference between alloying elements and impurities?

In carbon steels, in addition to the main elements using in Hi-tensile scaffolding - iron and carbon, there are others: manganese, sulfur, phosphorus, silicon, hydrogen and others. We consider them impurities and divide into several groups: Permanent includes sulfur, phosphorus, manganese and silicon.

They come in steel in small quantities, getting into it from cast iron or Hi-tensile scaffolding as deoxidizers.

Hi-tensile scaffolding

The hidden ones include hydrogen, oxygen and nitrogen. They are also present in any steel, falling into it during smelting. The random ones include copper, arsenic, lead, zinc, tin and other elements. They get into steel from charge materials and are considered a feature of the ore.

Each of the listed impurities is characterized by a certain percentage. So, manganese in steel, as a rule, is no more than 0.8%, silicon - no more than 0.4%, phosphorus - no more than 0.025%, sulfur - no more than 0.05%.

How impurities affect the properties of Hi-tensile scaffolding?

Impurities have different effects on the characteristics of Hi-tensile scaffolding:

  • Carbon (C) increases the hardness, strength and elasticity of steels, but reduces their ductility.
  • Silicon (Si) with a content of up to 0.4% in steel and manganese with a content of up to 0.8% do not have a noticeable effect on the properties.
  • Phosphorus (P) increases the strength and corrosion resistance of steels, but decreases their ductility and toughness.
  • Sulfur (S) increases the brittleness of steels at high temperatures, reduces their strength, ductility, weldability and corrosion resistance.
  • Nitrogen (N 2 ) and oxygen (O 2 ) reduce the toughness and ductility of steels.
  • Hydrogen (H 2 ) increases the brittleness of steels.

How alloying elements affect the properties of Hi-tensile scaffolding?

Alloying additives are introduced into Hi-tensile scaffolding to change their characteristics:

  • Chromium (Cr) increases the hardness, strength, impact strength, corrosion resistance, electrical resistance of steels, while reducing their coefficient of linear expansion and ductility.
  • Furthermore, Nickel (Ni) increases the ductility, toughness, corrosion resistance and impact resistance of steels.
  • Tungsten (W) increases the hardness and hardenability of steels.
  • Moreover, Molybdenum (Mo) increases the elasticity, corrosion resistance, tensile strength of steels and improves their hardenability.
  • Vanadium (V) increases the strength, hardness and density of steels.
  • Silicon (Si) increases the strength, elasticity, electrical resistance, heat resistance and hardness of steels.
  • Manganese (Mn) increases the hardness, wear resistance, impact resistance and hardenability of steels.
  • Cobalt (Co) increases impact strength, heat resistance and improves the magnetic properties of steels.
  • Aluminum (Al) improves the heat and scale resistance of steels for Hi-tensile scaffolding.
  • Moreover, Titanium (Ti) increases strength, corrosion resistance and improves the machinability of steels.
  • Niobium (Nb) increases the corrosion and acid resistance of steels.
  • Copper (Cu) increases the corrosion resistance and ductility of steels.
  • In addition, Cerium (Ce) increases the ductility and strength of steels.
  • Neodymium (Nd), cesium (Cs) and lanthanum (La) reduce the porosity of steels and improve surface quality.

 

Alloy steel types

Depending on the content of alloying elements, steel for Hi-tensile scaffolding comes into three types:

  • If alloying elements are less than 2.5%, steels we classify as low-alloyed.
  • Moreover, with their content from 2.5 to 10%,
  • If the alloying elements are more than 10%, steels come as high-alloyed.

Impurities are harmful or not?

Impurities are inevitably present in steels, but some of them are harmful (these include latent impurities), so they try to minimize their content. Alloying elements add to steels purposefully to improve their properties or to obtain specific characteristics.

How to choose the right electrodes?

Generally, welding works are in demand in construction, production and in everyday life. In this case, the final result depends not only on the skill of the welder, but also on the correct choice of electrodes.

What electrodes are made by manufacturers?

All manufactured electrodes is easy to divide into three groups:

Ø Non-metallic, non-melting

There are two types of them: carbon and graphite electrodes.

Ø Non-melting metal

These are tungsten, yttrium, lanthanum and throated electrodes.

Ø Melting coated metal

There are five types of them: bronze, aluminum, copper, cast iron and steel electrodes. In what follows, we will describe only coated metal consumable electrodes.

How it works and what tasks an electrode is needed for?

Basically, the electrode is a metal core comes with a coating. Hi-tensile scaffolding for Hi-tensile scaffolding. During welding, the core melts and participates in the formation of the seam. Furthermore, the coating has a different function: it burns and forms a gas cloud, which protects the molten metal from oxygen and nitrogen entering it.

During welding, the electrode solves several problems:

  • Stabilizes the process of burning an electric arc due to its saturation with free ions
  • Furthermore, provides the formation of slag over the weld, which reduces the cooling rate of the metal
  • Thanks to this, less non-metallic inclusions remain in it
  • Minimizes the negative effect of oxygen on the weld metal
  • Similarly, they chemically bind free oxygen
  • Improves the properties of the metal due to the introduction of alloying additives

The use of Hi-tensile scaffolding for cladding buildings

Internal and external surfaces of buildings finish with stainless steel sheets. This metal is easy to see in high traffic areas. Most often, they come with Hi-tensile scaffolding:

  • Front and side walls or their fragments.
  • Moreover, elevator portals.
  • Similarly, Ceilings.
  • The ends of the stairs.
  • In addition, Overlapping.
  • External slopes and cornices.

All of the listed stainless steel trim elements is easy to find in the foyer and on the floors of banks, government agencies, clinics, office and shopping centers. In all these and industrial sites, stainless steel can be Hi-tensile scaffolding as external cladding around the entire perimeter.

Hi-tensile scaffolding 2021

What current is Hi-tensile scaffolding to perform welding?

Both direct and alternating current are suitable for welding for Hi-tensile scaffolding, but they have certain features:

Generally, constant increases the speed of work and makes it possible to obtain good quality seams. Variable allows better protection of the weld pool, but increases the metal spatter and worsens the impact toughness of the weld metal. High-quality welding is important not only by the experience of the welder, but also by the correct selection of electrodes

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