Friday, 11 March 2016

How You can weld nickel aluminium bronzes?

How You can weld nickel aluminium bronzes?


Aluminium bronzes are copper alloys containing, amongst other additions, up to 14% by weight of aluminium. Nickel aluminium bronzes are a subset aluminium bronzes which also contain nickel and often iron and manganese. Nickel aluminium bronzes are generally stronger than other aluminium bronzes and possess a two phase (duplex) microstructure.

Nickel aluminium bronzes possess an alumina surface oxide that gives good corrosion resistance, however, this oxide can cause inclusions and other flaws during welding, if entrapped in the weld metal. Interpass and preweld cleaning must be employed to avoid this. As with all welding, general surface cleanliness will improve the quality of the weld.

All aluminium and nickel aluminium bronzes undergo metallurgical changes in the HAZ and weld areas following welding which may lead to deleterious effects on the corrosion properties of the component. Depending on the severity of the service conditions, a postweld heat treatment may be advisable.


Techniques for welding Ni-Al bronzes



Gas shielded techniques such as TIG (or gas tungsten arc welding (GTAW)) and MIG (or gas metal arc welding (GMAW)) are the recommended methods for joining these materials. These methods limit the oxidation of the weld pool and, by the action of the arc, disperse surface oxide. TIG and MIG may both be used for the root pass and fill, MIG being generally faster, but of a lower quality. Pulsed MIG welding may give improvements in controllability. Pure argon, pure helium or mixed argon/helium shielding gases are normally used.

Manual metal arc (MMA) (or shielded metal arc (SMA)) welding is also possible but results may be less satisfactory than for gas shielded techniques. Care must be taken not to cause surface oxide and/or slag entrapment.

Matching filler metals are normally selected when welding Ni-Al bronzes. Standards for consumables include: British Standard BS EN ISO 24373:2009 'Welding Consumables - Solid Wires and Rods for Fusion Welding of Copper and Copper Alloys - Classification'; AWS A5.6/A5.6M: 2008 'Specification for Covered Copper and Copper-Alloy Arc Welding Electrodes'; and AWS A5.7/A5.7M: 2007 'Specification for Copper and Copper-Alloy Bare Welding Rods and Electrodes'.


To Know More Details on Technology
Contact us or Enroll for the Welding Inspection Courses at Decibel.

Monday, 7 March 2016

How can the lack of fusion defects be prevented ?

How can the lack of fusion defects be prevented ?

  • use a sufficiently wide joint preparation
  • select welding parameters (high current level, short arc length, not too high a welding speed) to promote penetration into the joint side wall without causing flooding
  • ensure the electrode/gun angle and manipulation technique will give adequate side wall fusion
  • use weaving and dwell to improve side wall fusion providing there are no heat input restrictions
  • if arc blow occurs, reposition the current return, use AC (in MMA [SMA] welding) or demagnetise the steel

Join For PCN Welding Inspector Level 2 Program for Knowing More on Welding Technology and It's Details

http://decibelnde.com/weldinginspector.php

Tuesday, 9 February 2016

NEW COURSE - UT: THICKNESS MEASUREMENT & CORROSION MONITORING PCN LEVEL 2

FIRST COURSE STARTS 29 FEBRUARY WITH FURTHER DATES IN JUNE, SEPTEMBER AND NOVEMBER ANNOUNCED.

DETECTION AND MONITORING OF CORROSION AND DETERMINATION OF MATERIAL THICKNESS USING MANUAL ULTRASONIC TESTING IN STEEL COMPONENTS

Corrosion and erosion is a major issue facing asset management across most plants. The major oil and gas companies operating in the UK have worked alongside BINDT (British institute of Non-Destructive Testing) in accordance with PCN ISI GEN Appendix A to develop a training program to train technicians with a view to measuring the competency of personnel working in these areas on plant assets. This course is applicable to all personnel working in plant integrity across multiple industries.
    
Our IMechE Engineering Training Solutions have been cooperating in the development to produce a training program where certification will be issued to technicians who attend the course and pass the subsequent examinations.

The course will focus on:

- Corrosion and erosion mechanisms in plate, pipe and variables such as elbows, flanges, reducers etc.
- Assessment and identification of corrosion by echo-dynamic patterns and other NDT methods
- Accurate measurement of remaining wall thickness
- Understanding isometric drawings and related component symbols
- Understanding the effect of coatings on measurements
- A general view of coatings and understanding their purpose
- Understanding the purpose and different destructive testing methods
- An understanding of product technology including casting, forging, welding and heat treatment.
- Safety considerations
- A look at the various material types that may be encountered
- This course will be suitable to all plant engineers and inspectors

We will be launching the course in February 2016 at the Engineering Training Centre at Sheffield Business Park.

Tuesday, 2 February 2016

Launched Diploma in Quality Engineering

Latest IMECHE Funded Training program for quality control has been started at Decibel

New Course in Line for Corrosion Mapping

New BINDT approved PCN Level 2 courses for Corrosion mapping will be launching this February at our Sheffield Training Centre and extending to remaining global locations.

Interested participants may book their sets