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A Kazakhstan-based oil and gas engineering contractor placed an order for a comprehensive package of spectacle blinds, spacers, and spades in multiple materials - including 316/316L stainless steel and duplex UNS S31803 - for use in sour-service pipeline isolation systems. From technical clarification to final shipment, the entire order was completed on schedule with full third-party certification. |
Kazakhstan is one of Central Asia's most important energy producers, home to giant oilfields including Tengiz, Kashagan, and Karachaganak - collectively among the largest hydrocarbon reserves in the world. These fields produce crude oil and associated gas that is often rich in hydrogen sulfide (H₂S) and carbon dioxide (CO₂), making them classified as sour service environments under NACE MR0175 / ISO 15156.
In sour service, standard carbon steel flanges and pipeline isolation components can suffer rapid sulfide stress cracking (SSC) and hydrogen-induced cracking (HIC). This is why the customer's material specification required components manufactured to ASTM A240 316/316L stainless steel and UNS S31803 duplex stainless steel, both of which are pre-qualified for sour service under NACE MR0175. The order covered spectacle blinds, spacers, and spades - the key isolation devices used to positively shut off sections of piping during maintenance and turnarounds.
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A spectacle blind gets its name from its shape: it looks like a pair of eyeglasses. One "lens" is a solid disc (the blind) that completely blocks flow; the other is an open ring (the spacer/spade) that allows flow. By rotating the device, operators can safely isolate or reconnect any pipe section without removing the entire fitting. |
Oder Details: Complete Procurement List
The procurement requisition (No. AXHG004 / IK-AXHC001) covered 14 distinct line items across three material grades and three pressure classes (Class 150, Class 600, and Class 1500). The full item breakdown is as follows:
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Item |
Description |
Material |
Class |
Size (in) |
Standard |
Qty |
|
1 |
Spacer & Spade |
A516-70N S5 |
CL.150 |
28" |
ASME B16.48 / B16.47 SR.A |
2 PCS |
|
2 |
Spacer & Spade |
A240-316/316L (NACE) |
CL.150 |
10" |
ASME B16.48 |
2 PCS |
|
3 |
Spectacle Blind |
A516-70 |
CL.150 |
2" |
ASME B16.48 |
49 PCS |
|
4 |
Spectacle Blind |
A516-70 |
CL.150 |
3" |
ASME B16.48 |
12 PCS |
|
5 |
Spectacle Blind |
A516-70 |
CL.150 |
4" |
ASME B16.48 |
13 PCS |
|
6 |
Spectacle Blind |
A516-70 |
CL.150 |
6" |
ASME B16.48 |
14 PCS |
|
7 |
Spectacle Blind |
A516-70N S5 |
CL.150 |
1" |
ASME B16.48 |
1 PCS |
|
8 |
Spectacle Blind |
A240-316/316L (NACE) |
CL.150 |
2" |
ASME B16.48 |
2 PCS |
|
9 |
Spectacle Blind |
A240-316/316L (NACE) |
CL.150 |
6" |
ASME B16.48 |
3 PCS |
|
10 |
Spectacle Blind |
A240-UNS S31803 (NACE) |
CL.150 |
2" |
ASME B16.48 |
1 PCS |
|
11 |
Spectacle Blind |
A240-316/316L (NACE) |
CL.600 |
2" |
ASME B16.48 |
1 PCS |
|
12 |
Spectacle Blind |
A240-UNS S31803 (NACE) |
CL.600 |
3/4" |
ASME B16.48 |
1 PCS |
|
13 |
Spectacle Blind |
A240-UNS S31803 (NACE) |
CL.600 |
2" |
ASME B16.48 |
9 PCS |
|
14 |
Spectacle Blind |
A240-UNS S31803 (NACE) |
CL.1500 |
2" |
ASME B16.48 |
1 PCS |
Order Summary
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Requisition No. AXHG004 / IK-AXHC001 |
Product Types Spectacle Blinds, Spacers & Spades |
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Key Materials A240-316/316L, A240-UNS S31803, A516-70/70N |
Pressure Classes CL.150 / CL.600 / CL.1500 |
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Pipe Sizes 3/4" to 28" |
Governing Standard ASME B16.48 / NACE MR0175 |
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Destination Kazakhstan |
Loading Port Tianjin Port, China |
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Application Oil & Gas Sour Service Pipeline Isolation |
Production Cycle 35 Days |
Why Kazakhstan's Oil & Gas Projects Demand NACE-Qualified Materials?
Kazakhstan's premier oil and gas fields - particularly Kashagan in the Caspian Sea and Tengiz in the west - are notorious in the global industry for their extreme H₂S concentrations. Kashagan crude contains H₂S levels of up to 19% by volume, placing it among the most challenging sour environments on the planet. Equipment operating in such conditions must comply with NACE MR0175 / ISO 15156, the international standard for materials used in H₂S-containing environments.
The customer's choice of ASTM A240 316/316L for stainless line items reflects this requirement. 316/316L is qualified for sour service under NACE MR0175 in the annealed condition, offering resistance to chloride stress corrosion cracking alongside its well-known corrosion resistance. For higher-pressure or more aggressive lines, the customer specified UNS S31803 duplex stainless steel - a material that combines the strength of ferritic steel with the corrosion resistance of austenitic steel, and which NACE MR0175 pre-qualifies for H₂S partial pressures up to 50 psi.
The 28-inch A516-70N normalized carbon steel spacer and spade (Supplementary Requirement S5 - impact tested) reflects the large-diameter, high-volume trunk lines where corrosion inhibition programs allow carbon steel use, but low-temperature toughness is still required for Kazakhstan's continental climate, where winter temperatures can drop below −30°C in the western oil-producing regions.
Shipping and Certification Process
Given the complexity of this order - three material grades, three pressure classes, and pipe sizes ranging from 3/4-inch to 28 inches - our team worked closely with the customer to confirm all technical requirements before production commenced. Key steps in the process included:
Technical Review and MTC Confirmation
Before cutting any material, we verified that all plate and flat-bar stock held EN 10204 Type 3.1 mill test certificates, with actual measured chemistry and mechanical properties falling within the NACE MR0175 limits. For duplex S31803 items, we confirmed hardness ≤ 22 HRC (the NACE MR0175 limit for weld zones) on the finished component certificates.
ASME B16.48 Dimensional Compliance
All spectacle blinds were fabricated and inspected to ASME B16.48 dimensional tolerances. The 28-inch large-diameter spacer and spade followed ASME B16.47 Series A (MSS SP-44) flange face dimensions, as specified on the requisition.
Packaging for Overland and Multimodal Transport
Because Kazakhstan is a landlocked country, goods shipped from China transit through Russia or via the Caspian Sea port of Aktau. Our packaging team used wooden crates with moisture-barrier vapor phase inhibitor (VPI) wrapping for the stainless and duplex items, and painted + bagged packaging for the carbon steel A516-70 components, to ensure corrosion protection throughout the extended multimodal transit.
Documentation Package
The final shipment was accompanied by EN 10204 3.1 mill test certificates for all material grades, ASME B16.48 dimensional inspection reports, NACE MR0175 compliance declarations, packing lists, and commercial invoice - the complete documentation set required by Kazakhstani customs and the customer's quality plan.
