1. TECHNOLOGY FOR EXPLOSION STRESS RELIEVING IN WELDED JOINTS
OF METAL STRUCTURES
NATIONAL ACADEMY OF SCIENCES OF UKRAINE
The E.O. Paton Electric Welding Institute (PWI)

2. EXPLOSION STRESS RELIEVING IN WELDED JOINTS
1. TITLE
2. Contact Person
Dr. Leonid D. Dobrushin
The E.O. Paton Electric Welding Institute (PWI) of NAS of Ukraine
Department on Welding, Cutting and Treatment of Metals by Explosion
11 Bozhenko Str., Kiev, 03680, Ukraine
Tel./fax:
EXPLOSION STRESS RELIEVING IN WELDED JOINTS
TECHNOLOGY FOR EXPLOSION STRESS RELIEVING IN WELDED JOINTS OF METAL STRUCTURES

3. EXPLOSION STRESS RELIEVING IN WELDED JOINTS
3. Technology Description (Part 1)
Residual stresses inevitably occurring during fusion welding are hazardous for welded metal structures. They sharply decrease the reliability and life-time of welded joints. The existing traditional methods of stress relieving (thermal, vibration, rolling by rolls, etc.) are either ineffective or unacceptable.
The explosion treatment technology proposed is based on application of intensive relaxation processes and deformation on metal in shock waves generated by contact explosion. It permits relieving or inducing residual stresses, strengthening metal and changing its substructure.

4. EXPLOSION STRESS RELIEVING IN WELDED JOINTS
3. Technology Description (Part 2)
EXPLOSION STRESS RELIEVING IN WELDED JOINTS

5. EXPLOSION STRESS RELIEVING IN WELDED JOINTS
4. Process (Part 1)
EXPLOSION STRESS RELIEVING IN WELDED JOINTS
Typical Diagram of Residual Stresses in Welded Joints and Explosion Treatment Basic Schemes for Sheet Welded Joints: 1 – Explosive Charge; 2 – Base Metal

6. EXPLOSION STRESS RELIEVING IN WELDED JOINTS
4. Process (Part 2)
EXPLOSION STRESS RELIEVING IN WELDED JOINTS
Explosion Treatment Basic Schemes for Axisymmetric Metal Structures of Large (left) and Small Sizes (right): O – Circular Weld; q - Explosion Loading

7. EXPLOSION STRESS RELIEVING IN WELDED JOINTS
5. Equipment & Products (Part 1)
On the Left: Assembling of Detonating Cord for Explosion Treatment of Welded Joints in the Decomposer
On Top: Device for Magnetoelastic Strain-gauge Residual Stresses Control

8. EXPLOSION STRESS RELIEVING IN WELDED JOINTS
5. Equipment & Products (Part 2)
Instant Picture of the Explosion Stress Relieving of Welded Joints in the Decomposer (left) and View of the Imprints from Detonating Cord (right)
EXPLOSION STRESS RELIEVING IN WELDED JOINTS

9. EXPLOSION STRESS RELIEVING IN WELDED JOINTS

10. EXPLOSION STRESS RELIEVING IN WELDED JOINTS
6. Advantage of Technology
EXPLOSION STRESS RELIEVING IN WELDED JOINTS
The explosion treatment technology requires no special equipment and power supplies, provides considerable stress relieving in welded joints of metal structures and as a result improvement of:
- Resistance of corrosion cracking;
- Static and fatigue strength;
- Resistance of brittle structure;
- Other physical and mechanical properties of welded joints in metal structures.

11. EXPLOSION STRESS RELIEVING IN WELDED JOINTS
7. Industrial Application Fields (Part 1)
1. Vessels and reservoirs, operable in contact with hostile environment;
2. Pipelines of critical application;
3. Large dimension structures, produced with high requirements against accuracy of their geometry.

12. EXPLOSION STRESS RELIEVING IN WELDED JOINTS
7. Industrial Application Fields (Part 2)
EXPLOSION STRESS RELIEVING IN WELDED JOINTS
EXPERIENCE OF WORKS ON EXPLOSION STRESS RELIEVING CARRIED OUT IN RECENT TIMES AND CONDUCTING FOR THE PRESENT:
– Ural Aluminium Plant (Ural, Russia) – 24 decomposers of 1100 m3 capacity;
1973 – Dneprovski Aluminium Plant (Zaporozhye, Ukraine) – 12 decomposers of 1100 m3;
1976 – Pavlodarski Aluminium Plant (Pavlodar, Kazakhstan) – 26 decomposers of 1500 m3;
1976 – Birach Alumina Plant (Zvornik, Yugoslavia) – 24 decomposers of 2500 m3;
1982 – Nikolaevski Alumina Plant (Nikolaev, Ukraine) – 48 decomposers of 3000 m3;
2006 – Pavlodarski Aluminium Plant (Pavlodar, Kazakhstan) – 10 decomposers of 2500 m3;
2007 – Nikolaevski Alumina Plant (Nikolaev, Ukraine) – 15 decomposers of 5000 m3.
Totally 400,000 running meters of welded joints in 300 tanks of large dimensions were explosively treated and at least USD40,000,000 economical efficiency was provided

13. THANKS FOR YOUR ATTENTION!
8. Economic & Technology (Industrial) Benefits
1. Compare to the existing heat treatment technology the explosion treatment one is at least times cheaper;
2. Industrial benefits is at least USD100,000 depend on volume of works;
3. Maintenance cost reduction, production quality increase.
9. Estimated Cost & Period of Research
For R&D of technology for explosion stress relieving in welded joints of metal structures of the Customer’s interest the cost and period required are the matter of negotiations based on Technical Assignment of the Customer.
THANKS FOR YOUR ATTENTION!
EXPLOSION STRESS RELIEVING IN WELDED JOINTS