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API RP 934-C-2019 pdf free download

API RP 934-C-2019 pdf free download.Materials and Fabrication of 1 1 / 4 Cr- 1 / 2 Mo Steel Heavy Wall Pressure Vessels for High-pressure Hydrogen Service Operating at or Below 825 °F (440 °C).
This recommended practice (RP) covers materials and fabrication requirements for new 1 1 / 4 Cr- 1 / 2 Mo steel heavy wall pressure vessels and heat exchangers for high-temperature, high-pressure hydrogen service. It applies to vessels that are designed, fabricated, certified, and documented in accordance with ASME Section VIII, Division 1 or Division 2. This document may also be used as a resource for equipment fabricated of 1Cr- 1 / 2 Mo Steel. This document may also be used as a resource when planning to modify an existing heavy wall pressure vessel. The interior surfaces of these heavy wall pressure vessels may have an austenitic stainless steel or ferritic stainless steel weld overlay or cladding to provide additional corrosion resistance. For this recommended practice, “heavy wall” is defined as a shell thickness 2 in. (50 mm) or greater, but less than or equal to 4 in. (100 mm) at the time of mill heat treatment. At shell or head thicknesses greater than 4 in. (100 mm), 1 1 / 4 Cr- 1 / 2 Mo plates and forgings have been shown to have difficulty meeting the toughness requirements given in this document. Thick 1 1 / 4 Cr- 1 / 2 Mo forgings, such as integrally reinforced nozzles, flanges, tube sheets, channel covers, etc., can especially have difficulty meeting specified properties. 2 1 / 4 Cr-1Mo plates and forgings can be used as an alternative to ensure properties are met. Although outside of its scope, this document can be used as a resource for vessels down to 1 in. (25 mm) or lower in shell thickness, with changes defined by the purchaser. Multilayer vessels are outside the scope of this document. This recommended practice is not intended for use for equipment operating above 825 °F (440 °C) or in the creep range. API RP 934-E covers these higher-temperature applications.
4.2 The manufacturer’s design report (Manufacturer’s Data Book), which includes ASME Code strength calculations, and when applicable local stress analysis for extra loads, and other special design analyses, should show compliance with the purchaser’s design specification and other technical documents. 4.3 This RP does not cover design issues other than those listed as follows. a) The minimum design thickness shall not take any credit for the corrosion allowance or weld overlay or clad thickness, or a combination thereof. b) Weld seam layouts shall provide that all welds are accessible for NDE such as RT, UT, MT, and PT, both during fabrication and in-service. The use of external attachments that cover weld seams should be avoided and shall require the purchaser’s approval. c) Nozzle necks shall have transition to the vessel body as shown in the ASME Section VIII, Division 2, Table 4.2.13. With the purchaser’s approval, nozzles with nominal size 4 in. (100 mm) and less may be fabricated in accordance with the ASME Section VIII, Division 2, Table 4.2.10, Detail 3 through Detail 6, with integral reinforcement. d) Where possible, nozzle welds should be located without intersecting circumferential or longitudinal welds, unless otherwise approved by the purchaser (if approved, the purchaser should specify an additional NDE and NDE sequence). 5 Base Metal Requirements 5.1 Material Specifications 5.1.1 Pressure boundary base metals shall be in accordance with the applicable ASME specifications indicated in Table 1. Tubing is outside the scope of this document.
5.5.2 Tensile Test Requirements Tensile testing of plates and forging materials shall comply with the applicable code(s) and the following additional requirements: a) test coupon shall be heat treated to represent the maximum postweld heat treatment as specified in 3.1.6; b) tensile properties at room temperature shall meet the requirements of the applicable code(s). 5.5.3 Impact Testing Requirements Charpy V-notch (CVN) impact testing shall be performed for all 1 1 / 4 Cr- 1 / 2 Mo steel material (by heat) used for pressure-retaining components except bolting. CVN impact tests shall comply with the applicable code(s) and the following additional requirements. a) Test coupons from forgings shall be oriented transverse to the major direction of metal flow. b) Test coupons heat treated to represent both the maximum and minimum post weld heat treatments that the equipment are expected to receive during fabrication per 3.1.6 and 3.1.7 shall be tested and meet the following requirements. The minimum CVN impact values at 0 °F (–18 °C) shall be 40 ft-lbs (54 Joules) average of three specimens and 20 ft-lbs (27 Joules) minimum for a single specimen. In addition, if the MDMT is less than 0 °F (–18 C), ASME Code requirements for impact testing must also be met. If the impact tests at this MDMT of less than 0 °F (–18 °C) meet the 40/20 ft-lbs (54/27 Joules) criteria, retesting at 0 °F (–18 °C) is not needed.

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