ISO/TR 15608 Material Groups

Material group 51.2: Pure Titanium with 0,2 < O₂ ≤ 0,25 %

These unalloyed titanium grades have an excellent corrosion resistance property, excellent weldability and is used in a wide variety of applications. The corrosion resistance of Titanium is due to a stable, protective, and strongly adherent oxide film layer. This film forms instantly when a fresh surface is exposed to air or moisture. This film growth is accelerated under strong oxidizing conditions. The Titanium oxide film is capable of healing itself instantly in the presence of moisture or oxygen. Because of this, Titanium applications are common in the fabrication of process equipment of chemical industries.

Features of Titanium pure Group 51.2 ISO/TR 15608

Grade 2:
Moderate strength unalloyed Ti with excellent weldability, cold formability, and fabricability; “workhorse” and “garden variety” Ti grade for industrial service with excellent resistance to mildly reducing to highly oxidizing media with or without chlorides. Approved for sour service use under the NACE MR-01-75 Standard.
This grade material is mainly used in chemical industries where the parts are subjected to very harsh environments.

Grade 7:
Most resistant Ti alloy to corrosion in reducing acids and localized attack in hot halide media, with physical/mechanical properties equivalent to Grade 2, and excellent weldability/fabricability.

Grade 16:
Lower cost, leaner Pd version of Grade 7 with equivalent physical/mechanical properties, and similar corrosion resistance.

Grade 26:
Lower cost, Ru-containing alternative for Grade 7 with equivalent physical/mechanical properties and fabricability and similar corrosion resistance.

Welding of Titanium pure Group 51.2 ISO/TR 15608

Commercially pure titanium and most titanium alloys are readily welded by a number of welding processes being used today. The most common method of joining titanium is the gas Tungstenarc (GTAW) process and secondarily is the gas metal-arc (GMAW) process. The techniques for welding titanium resemble those employed with nickel alloys and stainless steels. To achieve sound welds with titanium, primary emphasis is placed on surface cleanliness and the correct use of inert gas shielding.
An essential requirement for successfully arc welding titanium is proper gas shielding. Care must be taken to ensure that inert atmosphere protection is maintained until the weld metal temperature cools below 426°C (800°F).

Typical materials in group 51.2

Name / Grade	Number	Standard	Product	Remarks
Ti 2	3.7035	DIN 17851	–	–
2 2 2 WPT 2 F-2 2 2	R50400 R50400 R50400 R50400 R50400 R50400 R50400	ASTM B-265 ASTM B-338 ASTM B-348 ASTM B-363 ASTM B-381 ASTM B-861 ASTM B-862	Plate & Sheet Smls. & welded tube Bar Smls. & welded fitting Forgings Smls. pipe Welded pipe	ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC
2H 2H 2H F-2H 2H 2H	R50400 R50400 R50400 R50400 R50400 R50400	ASTM B-265 ASTM B-338 ASTM B-348 ASTM B-381 ASTM B-861 ASTM B-862	Plate Smls. & welded tube Bar Forgings Smls. pipe Welded pipe	ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC
Ti 7	3.7235	DIN 17851	–	–
7 7 7 WPT 7 F-7 7 7	R52400 R52400 R52400 R52400 R52400 R52400 R52400	ASTM B-265 ASTM B-338 ASTM B-348 ASTM B-363 ASTM B-381 ASTM B-861 ASTM B-862	Plate & Sheet Smls. & welded tube Bar Smls. & welded fitting Forging Smls. pipe Welded pipe	ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC
7H 7H 7H WPT 7H F-7H 7H 7H	R52400 R52400 R52400 R52400 R52400 R52400 R52400	ASTM B-265 ASTM B-338 ASTM B-348 ASTM B-363 ASTM B-381 ASTM B-861 ASTM B-862	Plate Smls. & welded tube Bar Smls. & welded fitting Forging Smls. pipe Welded pipe	ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC
16 16 16 WPT 16 F-16 16 16	R52402 R52402 R52402 R52402 R52402 R52402 R52402	ASTM B-265 ASTM B-338 ASTM B-348 ASTM B-363 ASTM B-381 ASTM B-861 ASTM B-862	Plate Smls. & welded tube Bar Smls. & welded fitting Forging Smls. pipe Welded pipe	ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC
16H 16H 7H WPT 16H F-16H 16H 16H	R52402 R52402 R52402 R52402 R52402 R52402 R52402	ASTM B-265 ASTM B-338 ASTM B-348 ASTM B-363 ASTM B-381 ASTM B-861 ASTM B-862	Plate Smls. & welded tube Bar Smls. & welded fitting Forging Smls. pipe Welded pipe	ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC
26 26 26 WPT 26 F-26 26 26	R52404 R52404 R52404 R52404 R52404 R52404 R52404	ASTM B-265 ASTM B-338 ASTM B-348 ASTM B-363 ASTM B-381 ASTM B-861 ASTM B-862	Plate Smls. & welded tube Bar Smls. & welded fitting Forging Smls. pipe Welded pipe	ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC
26H 26H 26H WPT 26H F-26H 26H 26H	R52404 R52404 R52404 R52404 R52404 R52404 R52404	ASTM B-265 ASTM B-338 ASTM B-348 ASTM B-363 ASTM B-381 ASTM B-861 ASTM B-862	PPlate Smls. & welded tube Bar Smls. & welded fitting Forging Smls. pipe Welded pipe	ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC

Material Group 23.1 ISO/TR 15608 such as EN AW-6061:
Heat treatable aluminium-magnesium–silicon alloys.

EN AW-6061 is a typical alloy in this Al-Mg-Si alloy material group. Generally Al-Mg-Si alloys are precipitation-hardened aluminium alloys. They are commonly available in pre-tempered grades such as 6061-T4/T6 with specified yield strength R_p0,2 > 240 MPa (T6).

The most common temper heat treatment (description in EN 515) for 6061 aluminium is:
T4: Naturally aged to a stable condition
T6: Solution heat treated, quenched and artificially aged

Welding of EN AW-6061 alloy.

Welding of The materials are good weldable with the conventional processes (MIG and TIG). When heat treatable aluminium welded, they lose significant amount of their mechanical properties in the heat affected zone (HAZ). If the base metal being welded is in T4 temper, much of the original strength can be recovered after welding by proper post-ageing. If the base metal is welded in the T6- temper, it can be solution heat treated an aged after welding which will restore it to the T6-temper. However, an post weld heat treating an aging may sous additional problems.

EN AW-6061 alloy , the strength of the original T4 or T6 tempers is reduced in the HAZ due the over-heating. Full re-hardening would require a complete solution heat treatment followed by quenching and artificial aging; as result, the welded assembly will most likely be strongly distorted. Partial re-hardening after weldings is possible up to about 40% of the parent strength.
Therefore, it is recommended,

• to keep the energy input per unit length of weld as small as possible( to reduce width of HAZ)
• to weld AlMgSi alloys in the T4 temper followed by age hardening of the complete assembly (if possible).

Applications for : Piping and high pressure gas storage cylinders. According to EN 602, the use of the EN AW-6061 material is allowed for the contact with food.

Applications of Al-Mg-Alloys such EN AW-6061 alloy

Al-Mg-Alloy EN AW-6061is suitable for the manufacture of pressure vessels and piping in accordance with EN 1392 “Aluminum and aluminum alloys – Wrought and cast products – Particular requirements for products for the fabrication of pressure equipment” see table below.

Table: Weldability and pressurised applications for aluminium alloy material group 23.1 in acc. to EN 1392:

Material	Condition 1	Weldability	Application	min./max. Working Temp.
EN AW-6060	T42 T6 T8	yes	Pressure Vessel, Piping Pressure Vessel, Piping Pressure Vessel, Piping	-273/80 °C -273/160 °C -273/160 °C
EN AW-6061	T4 2 T6	yes	Pressure Vessel, Piping Pressure Vessel, Piping	-273/80 °C -273/160 °C
EN AW-6082	T4 2 T6 T8	yes	Pressure Vessel, Piping Pressure Vessel, Piping Pressure Vessel, Piping	-273/80 °C -273/160 °C -273/160 °C

Typical materials in group 23.1

Name / Grade	Number	Standard	Products	Remarks
EN AW-AlMgSi EN AW-AlMgSi	EN AW-6060 EN AW-6060	EN 754 EN 755	Cold drawn rod/bar and tube Extruded rod/bar, tube	EN 13445-8: No EN 13480-8: Yes
EN AW-AlMg1SiCu EN AW-AlMg1SiCu EN AW-AlMg1SiCu	EN AW-6061 EN AW-6061 EN AW-6061	EN 485 EN 754 EN 755	Plate, sheet, stripe Cold drawn rod/bar and tube Extruded rod/bar, tube	EN 13445-8: No EN 13480-8: Yes
EN AW-AlSi1MgMn EN AW-AlSi1MgMn	EN AW-6082 EN AW-6082	EN 754 EN 755	Cold drawn rod/bar and tube Extruded rod/bar, tube	EN 13445-8: No EN 13480-8: No
6061 6061 6061 6061 6061 6061 6061 6061 6061 WP6061 6061	A96061 A96061 A96061 A96061 A96061 A96061 A96061 A96061 A96061 A96061 A96061	ASTM B-209 ASTM B-210 ASTM B-211 ASTM B-221 ASTM B-234 ASTM B-241 ASTM B-247 ASTM B-308 ASTM B-345 ASTM B-361 ASTM B-547	Plate & sheet Smls. tube Bar & rod Bar & rod & shape Smls. tube Smls. pipe & tube Forgings Shape Smls. pipe & tube Fittings Welded tube	ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC
6063 6063 6063 6063 WP6063	A96063 A96063 A96063 A96063 A96063	ASTM B-210 ASTM B-211 ASTM B-241 ASTM B-345 ASTM B-361	Smls. tube Bar & rod Smls. pipe & tube Smls. pipe & tube Fittings	ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC

ISO/TR 15608 Material Group 6.3: Cr-Mo-V Steels such as material no. 1.7779 with
3,5 % ≤ Cr < 7,0 %, Mo ≤ 0,7 % and 0,45 < V ≤ 0,55 % such as material no. 1.7779

Features of low alloyed Cr-Mo-V steel (2.25Cr–1Mo–V)

Hydrosteel CrMo (V) steels with 0.5 % V offer better performance for petrochemical reactors compared to 10CrMo9-10 steels that means the specified yield strength and creep properties for this material is a lot of better compared to 10CrMo9-10 steel.
Depending on the heat treatment, the yield strength of 20CrMoV13-5-5 steel is in the range of Rp0,2 = 520 – 640 MPa.

Applications for low alloyed Cr-Mo-V (20CrMoV13-5-5) steel

This material may be used in all applications requiring service conditions under high temperature and high pressure of hydrogen. Steel for hydrogen service an elevated temperature and pressure is stell that not readily susceptible to decarbusation by hydrogen at elevated pressures and temperatures and thus to hydrogen and grain boundary embitterment. This characteristic is achieved ba adding alloying elements that from carbides at the operating temperature.

Is particularly suitable for pressure equipment in high temperature hydrogen service (e.g. hydro treating reactors, exchangers, hydro treating reactors, hydro desulfurizers, hydro crackers)

Welding conditions for 20CrMoV13-5-5 steel

Welding needs precautions, in particular: tight control of preheat, interpass temperature intermediate stress relieving and post weld heating to avoid cold cracking;

Weld metal and HAZ in the as welded condition are susceptible to hydrogen induced cold cracking.

However, the risk of cold cracking is known to occur in the weld metal more frequently than in the HAZ. Therefore, a preheat and minimum interpass temperature of 200°C is recommended for thickness higher than 30 mm. After welding a Dehydrogenation Heat Treatment ≥ 300 °C is recommended. After welding, these steels generally have to be PWHT e.g. 700 -730 °C.

Name	Number	Standard	Product	Remark
20CrMoV13-5-5 D, Cl. 4a	1.7779 K31835	EN 10216-2 ASTM A-542	Smls. tube Forging	EN 13445-2 & EN 13480-2 ASME BPVC

Material Group 51.3 ISO/TR 15608: Pure titanium with 0,25 < O₂ ≤ 0,35 %

Features of Titanium pure Group 51.3 ISO/TR 15608

Grade 3:
Moderate strength unalloyed Ti with excellent weldability, cold formability, and fabricability. Slightly stronger version of Gr. 2 Ti with similar corrosion resistance with good weldability and reasonable cold formability/ductility.
This grade material is mainly used in chemical industries and power plant cooling system components where the parts are subjected to very harsh environments.

Welding of Titanium pure Group 51.3 ISO/TR 15608

Commercially pure titanium and most titanium alloys are readily welded by a number of welding processes being used today. The most common method of joining titanium is the gas Tungstenarc (GTAW) process and secondarily is the gas metal-arc (GMAW) process. The techniques for welding titanium resemble those employed with nickel alloys and stainless steels. To achieve sound welds with titanium, primary emphasis is placed on surface cleanliness and the correct use of inert gas shielding.
An essential requirement for successfully arc welding titanium is proper gas shielding. Care must be taken to ensure that inert atmosphere protection is maintained until the weld metal temperature cools below 426°C (800°F).

Typical materials in group 51.3

Name / Grade	Number	Standard	Product	Remarks
Ti 3	3.7055	DIN 17851	–	–
3 3 WPT 3 F-3 3	R50550 R50550 R50550 R50550 R50550	ASTM B-265 ASTM B-338 ASTM B-363 ASTM B-381 ASTM B-862	Plate & sheet Smls. & welded tube Fitting Forgings Welded pipe	ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC

ISO/TR 15608 Material Group 3.2: Quenched and tempered (QT) fine-grain high strength steels with a specific minimum yield strength R_eH > 690 N/mm².

What is the quenched and tempering (QT) process of high strength steels?

Quenching and tempering is a heat-treatment method for high strength low alloy steel. Quenching and tempering consists of a two-stage heat-treatment process. 
Stage 1 includes hardening, in which the plate is austenitised to approximately 900°C and then quickly cooled. The material is water-quenched in a quench unit, in which the plate is clamped to avoid warpage. 
Stage 2 consists of tempering the material to obtain the desired material properties. Quenching and tempering achieves an extremely fine-grained and homogeneous microstructure. Quenched and tempered steel is characterised by high strength and good ductility.

Weldability of high strength steels ISO/TR 15608 Material Group 3.2

The high-strength tempered materials are generally weldable. However, certain requirements must be met during welding with regard to heat input and controlled cooling in the heat-affected zone and the use of hydrogen-reduced weld metal

When welding high strength steels, it should be noticed that that a tempering effect occurs due to the heat input during welding, which influences the properties of the base material. The temperature-time cycles during welding have a significant effect on the mechanical properties of a welded joint and the heat effect zones. It is understood, that the t8/5-time is sufficient to describe the temperature-time characteristics. t8/5 is the cooling time from 800°C to 500°C and describes the cooling conditions of an individual weld pass for the weld metal and the corresponding heat affected zone (HAZ). t8/5 depends on the heat input during welding, the plate temperature (or interpass temperature), the shape factor (geometry) and on plate thickness if two dimensional heat flow occurs which is generally the case for thin plates. To achieve satisfactory weld metal properties the welding parameters must be limited with increasing yield strength. For example acceptable properties for an P960QL steel are normally obtained with cooling times between 5 s and 20 s. For lower cooling times the hardness of the heat affected zone may exceed limiting values with the risk of introducing cracks.

The hydrogen content of the consumables H2 has a significant influence on the preheating temperature. In order to reduce the risk of hydrogen-induced cracking the preheating temperature must be increased with growing hydrogen content.

Flame straightening of high strength steels ISO/TR 15608 Material Group 3.2

The maximum recommended temperatures for flame straightening is usually 550°C for quenched and tempered steels.

Quenched and tempered (QT) fine-grain steels with a specific minimum yield strength 460 < R_eH ≤ 690 N/mm²: see Group 3.1

Typical materials in group 3.2

Name / Grade	Number	Standard	Product	Remarks
S700MC	1.8974	EN 10149-2	Plate	for cold forming
S900MC	1.8798	EN 10149-2	Plate	for cold forming
S690MC	1.8799	EN 10149-2	Plate	for cold forming
S890Q	1.8940	EN 10025-6	Plate	structural steels
S890QL	1.8983	EN 10025-6	Plate	structural steels
S890QL1	1.8925	EN 10025-6	Plate	structural steels
S960Q	1.8941	EN 10025-6	Plate	structural steels
S960QL	1.8933	EN 10025-6	Plate	structural steels
A, Cl. 1 A, Cl. 2 A, Cl. 3	K12521 K12521 K12521	ASTM A-533 ASTM A-533 ASTM A-533	Plate Plate Plate	ASME BPVC ASME BPVC ASME BPVC
J100	K12521	ASTM A-672	Fusion welded pipe	ASME BPVC

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