P500Q quenched and tempered fine grain steel pressure vessel plate
P500Q PRESSURE VESSEL STEEL is a vacuum treated quenched and tempered fine grained steel. It is predominantly applied for pressure vessels e.g. in offshore and onshore constructions where weight saving is a very important parameter.
Due to its production route and its chemical composition P500Q PRESSURE VESSEL STEEL has excellent mechanical properties combined with good weldability. P500Q PRESSURE VESSEL STEEL comply with EN 10 028-6 or ASTM/ASME A/SA 533 Type C.
Product description
Designation and range of application
P500Q PRESSURE VESSEL STEEL can be delivered in two grades as follows:
• High tensile strength grade (HT) with minimum tensile strength of 600 N/mm² and a minimum yield strength of 500 N/mm²
• Sour service grade (S) with minimum tensile strength of 580 N/mm² and a minimum yield strength of 460 N/mm² fulfilling additional sour service requirements
This specification applies to plate thicknesses from 10 to 130 mm.
Chemical composition according to heat analysis (in %)
| C | Si | Mn | P | S | N | Al | Cu | Mo | Ni | Cr |
| ≤0.13 | ≤0.40 | 1.00-1.60 | ≤0.012 | ≤0.002 | ≤0.01 | ≥0.015 | ≤0.30 | ≤0.60 | ≤1.20 | ≤0.60 |
V+Nb≤0.01%
Delivery condition
Water quenched and tempered; if the heat treatment is to be performed after forming, delivery in the as rolled condition is possible. In this case the testing of the mechanical and technological properties is provided on the basis of simulated heat treated specimens.
Mechanical properties in the delivery condition
Tensile test at ambient temperature for all plate thicknesses (transverse test specimens)
| yield strength ReH, N/mm² minimum | tensile strength Rm, N/mm² | elongation A5 %, minimum |
| 500 | 600-770 | 18 |
For plate thicknesses ≥ 15 mm, the adherence to grades Z15, Z25 or Z35 in accordance with EN 10 164 or comparable regulations, which are characterized by a minimum reduction of area on through-thickness tensile test specimens, can be stipulated on the order.
Tensile properties at higher temperatures *) (transverse test specimens)
| | test temperature °C |
| | 100 | 150 | 200 | 250 | 300 |
| minimum yield strength Rp0,2 | 90% | 88% | 86% | 82% | 82% |
| minimum tensile strength Rm | 88% | 86% | 85% | 82% | 82% |
*) Percentage of specified minimum value at room temperature
Unless otherwise agreed, the high temperature tensile test is carried out at 150 °C
Impact test with Charpy-V specimens (specimens’ location in accordance with EN 10 028-1)
| test temperature in °C | minimum impact value in J (transverse test specimens) |
| - 50 | 50 |
The specified value is the minimum value for the average of three tests. No individual value is to be less than 70 %
of the specified minimum.
Toughness requirements at other temperatures can be agreed upon on the inquiry.
Impact test with specimens taken in mid-thickness can be agreed upon on the inquiry.
Sour service requirements
P500Q PRESSURE VESSEL STEEL S fulfills the following requirements:
• hardness requirements as per NACE standard MR 0175
• other requirements upon agreement on the inquiry
Testing
Unless otherwise agreed, sampling, testing method and tests are in accordance with the provisions in EN 10 028. The plates are delivered with inspection certificate or inspection report in accordance with EN 10 204. The document type and, if the tests are not to be performed by the manufacturer’s expert, the inspection body are to be stated on the order.
Identification
Unless otherwise agreed, the marking is carried out with low stress stamps bearing at least the following information:
• manufacturer’s symbol
• steel designation
• heat number
• number of rolled plate/single plate
• inspector’s stamp
Fabrication properties
The entire fabrication and application techniques are of fundamental importance to the reliability of the products made from these steels. The fabricator should ensure that his calculations, design and fabricating methods are aligned with the material, are state-of-the-art and suitable for the intended use. The customer is responsible for the selection of the material.
Forming properties
P500Q PRESSURE VESSEL STEEL can be hot or cold formed. Cold forming can be performed at room temperature or at a temperature 50-100 °C below the tempering temperature. For both cases it must be generally taken into account that the plates’ original toughness level will be reduced by cold forming. If forming is done at temperatures above the tempering temperature indicated in the plate certificate a further complete heat treatment (quenching and tempering) is necessary. For a further heat treatment of the steels it has to be taken into account that, due to e.g. different heat treatment facilities, it is not always possible to achieve the same properties as at the original heat treatment.
Heat treatment
• Austenitizing and tempering treatment:
Austenitizing at 890 - 950 °C, water quenching.
Tempering after water quenching according to the manufacturer’s recommendations.
• Stress relieving treatment at 550 - 620 °C, holding time at least 30 min; for holding times exceeding 3 h or higher temperature.
General technical delivery requirements
Unless otherwise agreed, the general technical delivery requirements in accordance with EN 10 021 apply.
Tolerances
Unless otherwise agreed, tolerances are in accordance with EN 10 029, with class B for the thickness.
Surface condition
Unless otherwise agreed, the indications in accordance with EN 10 163 class B2 apply.
General notes
If special requirements, which are not listed in this specification, have to be met by the steel due to its intended use or processing, these requirements have to be agreed before placing the order.
Production process
