Welded Tube Production – Balçık Tube

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Welded Tube Production

WELDED TUBE

Thanks to the consumption and requirement of our Heating Element division for the Welded Stainless Steel Tubes, we have founded the BALÇIK Tube division and offering high-quality Stainless Steel Tubes and Tube products, which find use in a wide range of applications.

Based on large know-how and experience in tube manufacturing for more than 15 years, in our production site, high-quality BALÇIK Stainless Steel Tubes with diameters from 6,0 mm to 13,0 mm are TIG welded.

Stainless Steel Welded Tubes can be ordered in various dimensions:
Outside diameter: 6,0 - 13,0 mm
Wall thickness: 0,25 - 1,0 mm
Length: 20 - 8.000 mm

We have significant stock of tubes and raw material and can quickly satisfy customer’s requests with timely supplies even for small quantities.

Technological Process
Roll-forming of cold-rolled strips of stainless steel or alloys with high content of nickel to the required diameter, TIG welding in inert atmosphere, sizing of outside diameter, heat treatment at 1040-1100°C.

Extremely precise production techniques guarantee the high performance of BALÇIK Stainless Steel Tubes:

• TIG welding with welding factor V = 1,0
• Annealing within inert gas atmosphere
• Leakage test
• Various tube end treatments for example
– Burr-free cutting,
– Inside and/or outside countersink deburring
– Low burr sawing
– Brush deburring
Vibratory grinding
• Defined roughness of welding seam
• Defined increase of inner welding seam

We optimize the complete production process in-house in order to achieve best final tube products starting from the selection of high-quality strip material to the adjustment of all production steps.

Our own laboratory analyzes and approves tubes or materials for our customers with up-to-date and high-equipped test devices.

We ensure high quality due to strict controls which accompany every phase of the production process. We rely on a modern and well-equipped laboratory to monitor the quality. Diverse methods for analyzing the physical, metallographic and chemical properties of materials are available.

These methods especially include:
Tensile tests: yield point, tensile strength, elongation
Chemical analyses with a stationary metal analyzer and ICP-OES
Hardness tests
Measurements of roughness
Material tests with digital processing of images; by means of a scanning electron microscope
X-ray tests
Extensive investigations into corrosion resistance

BALÇIK Stainless Steel Tubes and Tube products comply with the following standards;

EN10088-2 Raw material technical specifications (strip)
EN10217-7 General reference standard for welded stainless steel circular tubes for pressure equipment
DIN 54141 Process control (Eddy current or Foucault current test) with cutting and automatic selection of tube with possibile surface variations.
Non destructive test, carried out on the production line
EN ISO 8493 Diameter expansion test, 30% minimun, without detecting cracks
Destructive test, carried out on samples out of the production line
EN ISO 8492 Back bending test of the welding area
Destructive test, carried out on samples out of the production line
EN 10204 Metallic materials: types of inspection documents
ASTM A 249/A Technical reference norm for heat-treated tubes to be used for heat exchangers and boilers
ASME
SA-312/SA312-M Specification for seamless and welded austenitic stainless steel pipes

Pressure test in air at 10 Bar for 10 min. or, in conformity with EN 10217-7 norm, in water at 70 Bar or up to 300 Bar on request.

All tubes are marked with identification code of producer, in addition to diameter, thickness, alloy and specific production information to guarantee that all data about them are traceable.

Tube in bars is packed in:
stackable wooden boxes, fixed with straps
stackable wooden boxes, fixed with straps and cover
appropriate wooden crates for tubes cut to length
bundles, fixed on wooden boards with straps
made-to-measure wooden packages, fixed with straps for tubes up to 20 m long.

All types of packing guarantee the preservation of all the dimensional and sanitary characteristic of the product.

Heat Treatment for Tubes - Online Bright Annealing Technology

A heat treat process performed online thru our tube mills by a carefully controlled furnace atmosphere resulting in a clean, smooth, scale free metal surface. During typical open annealing, the heated steel combines with oxygen in the air to form an oxide layer on the steels surface. In bright annealing, the steel is heated in a furnace filled with gases, such as hydrogen or nitrogen, to prevent oxide scale formation. The material comes out of the bright anneal furnace with the same surface as it had when it went into the furnace.

Bright annealing is carried out in a furnace full of Hydrogen (H2) at temperatures ranging between 1040 ° C and 1100° C and is followed by a rapid cooling. The Hydrogen is NOT an oxidising agent and therefore no surface oxidation is created and pickling is no longer required after the bright annealing.

The main advantage of this system, besides a bright and even surface that eases further processing of the tubes, is the improved corrosion resistance of the material. Such treatment, carried out at the ﬁnal stage of the production process, ensures the complete solution of the possible carbides precipitated at the grain border, thus obtaining an austenitic matrix free of defects. This makes it possible to avoid the dangerous phenomena of intergranular corrosion.
The austenitic structure obtained through on-line bright annealing, is homogeneous with regular grain size; the consequence is an improvement of stainless steel tensile properties, in particular traction and elongation, with an increase of plasticity and a decrease of residual stress. This is a a material characteristic very well appreciated by all end users who are making further manipulations on tubes such as bending and forming.