ISO 15614-8:2016

Overview

ISO 15614-8:2016 - Specification and qualification of welding procedures for metallic materials - Welding procedure test - Part 8: Welding of tubes to tube-plate joints, specifies requirements for the qualification testing of welding procedures for the arc welding of tubes to tube-plate joints. It covers manual, partly mechanized, fully mechanized and automatic arc welding processes for fusion-welded tube-to-tube-plate assemblies where a gap exists between tube and plate through part of the plate thickness. The standard is part of the ISO 15614 series (see ISO 15607, Annex A) and focuses on procedure qualification rather than design rules.

Key topics and requirements

• Scope and applicability: Qualification by tube-to-tube-plate tests can be used for fully loaded joints or seal welds as required by application standards. The standard excludes tube-sheets with forged end connections welded in the bore (external/internal bore welds).
• Welding processes covered: Manual, partly mechanized, fully mechanized and automatic arc welding of metallic materials for tube-to-tube-plate joints.
• Preliminary Welding Procedure Specification (pWPS): Items to be specified before testing, covering general and process-specific parameters.
• Procedure qualification (WPQR): Requirements for preparing test pieces, performing welding under production-like conditions, and documenting a Welding Procedure Qualification Record.
• Test-piece construction: Guidance on joint preparation, tube/plate dimensions and representative test-piece arrangements to simulate production conditions (pitch, restraint, heat-sink effects).
• Examination and testing: Mandatory and optional examinations including visual testing, penetrant testing, radiographic testing, macroscopic examination, hardness testing and push-out/pull-out tests to verify joint integrity and load-bearing capacity.
• Range of qualification: Rules that define how the qualified procedure can be applied across materials, tube/plate dimensions, filler metals, welding positions, heat input, preheat/interpass/post-weld heat treatment and shielding gases.
• Repair welding: Repair procedures are to be considered within the welding procedure test.
• Special cases: For mechanically expanded, load-bearing tube joints, a specific welding procedure test should be defined in the project specification.

Practical applications - who uses ISO 15614-8:2016

• Welding engineers and procedure authors preparing WPQRs/WPSs for heat exchangers, boilers, condensers and tube bundles.
• Fabricators and manufacturers of pressure equipment and heat-transfer assemblies where tube-to-tube-plate joints are common.
• Inspection bodies, third-party auditors and quality managers verifying procedure qualification and compliance.
• Plant owners in petrochemical, power generation, HVAC and chemical processing industries requiring certified welding procedures for tube assemblies.

Related standards

• ISO 15607 (general rules for procedure qualification)
• ISO 15614-1 (welding procedure tests for steels & nickel alloys)
• ISO 15609-1 (WPS - arc welding)
• ISO 17636-1 (radiographic testing)
• ISO 17639 (macroscopic/microscopic examination)
• ISO 14175 (shielding gases) and ISO 9606 series (welder qualification)

Keywords: ISO 15614-8, welding procedure qualification, tube to tube-plate joints, WPQR, arc welding, radiographic testing, push-out test, fusion welding.