The above and you explain why the surface brightness ≠ surface roughness, this time to answer the customer's question - "why other people's pipes look brighter than Xinlai's"
.
In-line bright solution treatment
Why solution treatment
In the production process, stainless steel pipes are affected by high temperatures during rolling, stretching and welding, so that the structure and mechanical properties of the materials will change, which affects the quality of stainless steel pipes:
01 Poor metallographic materialization
During pipe making, the base metal is welded to form a heat-affected zone, and its internal phases have different microstructures: ferrite, martensite, austenite and other metallographic structures, which greatly affect the corrosion
resistance of the pipeline.
All kinds of metallographic structures
02 Stress generation
The internal lattice of the base metal is distorted and distorted, the grain is sheared and slipped, the grain is elongated, and after the lattice is distorted, a significant stress concentration area will be formed, also known as dislocation, and the pipeline is prone to deformation
.
Dislocation schematic
Through solution treatment, each phase in the pipe can be fully dissolved, the grain can be refined, and the toughness and corrosion resistance can be improved, and the stress and softening can be relieved for continued processing or molding
.
Online bright solid solution
Compared with the ordinary annealing process, online bright solution technology can not only heat treat stress relief, but also improve the mechanical properties of materials, microstructure hardness and a series of treatments, improve pipeline toughness and corrosion resistance
.
Online bright solid solution
Principle: Bright annealing refers to the process in which the stainless steel tube is heated to 1040~1100 °C under the protection of pure hydrogen in the process of stainless steel tube tube, and quickly cooled to normal temperature under the protection
of pure hydrogen.
Impact: On the one hand, the internal stress is eliminated, on the other hand, the weld bead is treated with high temperature solution to refine the grain structure, the ferrite content is greatly reduced, and the corrosion
resistance of the pipeline is improved.
Xinlai BA low-carbon stainless steel pipe adopts online bright solution technology, which has obvious advantages compared with other food-grade stainless steel pipes:
The hazards of cloth wheel polishing
The pipe that needs to be polished is more harmful, and the polishing of the cloth wheel is generally only used as a decorative stainless steel surface treatment, which can obtain a very good mirror effect, but can not optimize the surface roughness, but becomes a shoddy gimmick
.
Cloth wheel polishing + polishing paste
Hygienic dead angle: After polishing, although the Ra value may be good, many crack dead spots can be observed under the electron microscope, hiding dirt!
Welding influence: during polishing, the surface is mixed with many impurities and grinding particles, and a hardened deformation layer will be formed after cooling, and welding is prone to solder joint corrosion, causing leakage and polluting the product
.
Polishing paste: the use of animal-derived ingredients as polishing agents, will be heat penetration into the pipeline during the polishing process, and the use process is slowly released, resulting in production pollution, in Europe and the United States affected by prion mad cow disease, it is strictly forbidden to make such polishing agents.
Therefore, in the latest version of ASMEBPE's GR8 chapter, it is strictly forbidden to use cloth wheel polishing on food and drug contact surfaces; EHEDG prohibits the use of polishes
with animal-derived ingredients.
Xinlai BA low carbon stainless steel pipe Bright Annealing
Xinlai BA low carbon stainless steel pipe, using bright annealing process (Bright Annealing), no need for machine throwing, surface roughness value Ra≤0.
8μ, carbon content ≤ 0.
03%, very few impurities, good intergranular structure recovery during welding, non-magnetic
.
The pipeline treated by the bright annealing process can eliminate internal stress on the one hand, and form a passivation film on the surface of the pipe on the other hand, so as to improve the corrosion resistance
of the pipeline.
Advantages of BA pipes
· No machine throwing, no pickling
· The inner surface roughness value Ra≤0.
8
· Carbon content≤ 0.
03%
· The intergranular structure of the weld bead is well recovered and non-magnetic
· The internal weld bead flattening process is excellent, and the surface roughness of the weld is ≤0.
8um, or even better
· Further improve corrosion resistance
Next, we will take you through a set of comparative experiments to understand the difference between Xinlai BA pipeline and other food-grade pipelines more
straightforwardly.
Stainless steel pipe weld bead inspection
01
Weld bead ferrite content detection
The content of solid solution tubes of other brands was measured at 3.
9%
Xinlai brand solid solution tube content measured 1.
5%
02
Permeability testing of weld beads
The content of solid solution tubes of other brands was measured to be 1.
15
The content of Xinlai brand solid solution tube was measured 1.
05
03
Weld bead magnet adsorption detection
Other brands of solid solution tube adsorption - strong
Xinlai brand solid solution tube adsorption - weak
04
Weld bead hydrochloric acid corrosion test
Other brands of solid solution tubes are thinned from 1.
17 to 0.
28mm
Xinlai brand solid solution tube was thinned from 1.
23 to 0.
92mm
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