One Step Further: 500 MPa Yield Strength Steel for Offshore Constructions

2002 ◽  
Author(s):  
F. Hanus ◽  
J. Schu¨tz ◽  
W. Schu¨tz
Keyword(s):  
Yield Strength ◽  
Base Material ◽  
Steel Grade ◽  
The North ◽  
Single Piece ◽  
Research Programmes ◽  
The North Sea ◽  
One Step ◽  
Haz Toughness ◽  
Minimum Yield

Essential savings in time and money can be achieved if the topside of an offshore platform can be installed in a single piece. For the projects Grane and Valhall located in the North Sea this goal could only be met by using steels with a minimum yield strength of 500 MPa. At the same time the steel should be as easily weldable as the 420 MPa TMCP steel that had become a common offshore steel grade in Norway during the last decade. Based on profound experience in TMCP and research programmes on weldability a chemical composition was selected promising to scope the requirements for base material and HAZ. A few plates were first produced and tested successfully. Excellent weldability in terms of HAZ toughness and low preheat was proven through a vast qualification programme and test welds at the yards. In the first part of the 3500 t order for Valhall the process parameters were optimised to achieve stable properties for the whole thickness range from 15 to 80 mm. The development of this steel grade S500M3z, the results and experience gained on the first deliveries shall be presented in the paper.

XABO 355

Alloy Digest ◽  
2017 ◽  
Vol 66 (1) ◽  
Keyword(s):  
Fracture Toughness ◽  
Yield Strength ◽  
Physical Properties ◽  
Flat Plate ◽  
Structural Steel ◽  
Tensile Properties ◽  
Impact Test ◽  
Steel Grade ◽  
Minimum Yield

Abstract XABO 355 (minimum yield strength of 355 MPa, or 51 ksi, for thicknesses up to 35 mm, or 1.4 in.) is a thermomechanically rolled structural steel. This datasheet applies to thermomechanically rolled flat plate products in thicknesses up to 60 mm (2.4 in.). This steel grade is distinguished by testing by notch-bar impact test to –20 deg C (-4 deg F) minimum. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on forming and joining. Filing Code: SA-777. Producer or source: ThyssenKrupp Steel Europe AG.

XABO 500

Alloy Digest ◽  
2017 ◽  
Vol 66 (6) ◽  
Keyword(s):  
Yield Strength ◽  
Physical Properties ◽  
Flat Plate ◽  
Structural Steel ◽  
Tensile Properties ◽  
Impact Test ◽  
Steel Grade ◽  
Minimum Yield

Abstract XABO 500 (minimum yield strength of 500 MPa, or 73 ksi, for thicknesses up to 16 mm, or 0.6 in.) is a thermomechanically rolled structural steel. This datasheet applies to thermomechanically rolled flat plate products in thicknesses up to 60 mm (2.4 in.). This steel grade is distinguished by testing by notch-bar impact test to –20 deg C (-4 deg F) minimum. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on forming and joining. Filing Code: SA-786. Producer or source: ThyssenKrupp Steel Europe AG.

scholarly journals Depensation, probability of fertilization, and the mating system of Atlantic cod (Gadus morhua L.)

2004 ◽  
Vol 61 (7) ◽  
pp. 1144-1150 ◽  
Author(s):  
Sherrylynn Rowe ◽  
Jeffrey A. Hutchings ◽  
Dorte Bekkevold ◽  
Ana Rakitin
Keyword(s):  
Population Size ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Fertilization Rate ◽  
Effective Population ◽  
Broadcast Spawning ◽  
The North ◽  
Research Programmes ◽  
The North Sea ◽  
Census Population Size

Abstract Atlantic cod (Gadus morhua L.) have been severely overexploited and are currently at historic population lows, having declined 90% in the North Sea and 99% off northeast Newfoundland in recent decades. Slow rates of recovery and continuing declines may be attributable to depensation, defined as a reduction in per capita growth rate concomitant with reduced population size. Several potential causes of depensation relate to low mating success and consequent reduced production of offspring. We explore the empirical basis of one of these in Atlantic cod using egg fertilization and male abundance data obtained from 21 experimental populations generated by three independent research programmes. We find support for the hypotheses that (a) fertilization rate declines with abundance and (b) variance in fertilization rate increases as population size declines. The former identifies one potential mechanism underlying depensation in Atlantic cod. The latter has negative genetic consequences for effective population size (Ne), resulting in a decline in the ratio of Ne to census population size (Ne/Nc) with declining abundance. Our results may have general implications for the conservation biology of broadcast-spawning marine fish, particularly those with mating systems similar to that of Atlantic cod.

XABO 460

Alloy Digest ◽  
2017 ◽  
Vol 66 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Yield Strength ◽  
Physical Properties ◽  
Flat Plate ◽  
Structural Steel ◽  
Tensile Properties ◽  
Impact Test ◽  
Steel Grade ◽  
Minimum Yield

Abstract XABO 460 (minimum yield strength of 460 MPa, or 67 ksi, for thicknesses up to 35 mm, or 1.4 in.) is a thermomechanically rolled structural steel. This datasheet applies to thermomechanically rolled flat plate products in thicknesses up to 60 mm (2.4 in.). This steel grade is distinguished by testing by notch-bar impact test to –20 deg C (-4 deg F) minimum. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on forming and joining. Filing Code: SA-778. Producer or source: ThyssenKrupp Steel Europe AG.

35 Year Old Jackets Removed as a Single Piece

2011 ◽  
Author(s):  
Jochum C. G. van Hoof ◽  
Ruben de Bruin
Keyword(s):  
Dynamic Behavior ◽  
Wave Climate ◽  
Model Tests ◽  
Time Model ◽  
Project Duration ◽  
The North ◽  
Transport Distance ◽  
Single Piece ◽  
Heavy Lift ◽  
The North Sea

Heerema Marine Contractors (HMC) have removed and will be removing various platforms from the North Sea. For these projects Heerema has developed an unconventional method to remove and transport jackets: Jackets are lifted as one single piece and transported to the recycling yard whilst being suspended from both cranes of the Heavy Lift Vessel (HLV) Thialf. Two purpose built structures at the stern restrain the jackets from horizontal motions during transport. In summer 2010 three eight-legged jackets were removed and transported using this method (see Figure 1). The jackets weighed approximately 5,000 metric tonnes each and stood in 70–80m of water. The jacket removal resulted in load cases that were never considered during jacket design. Jacket strength appeared very marginal when cutting the jacket into several sections, but by lifting the jacket as one single section, all members remained connected and ensured a stable structure. Other benefits were reduction of the offshore project duration, the subsea cutting scope and the required vessel spread. Risk on weather downtime was reduced and safety improved by preventing back loading operations in an offshore environment. The transport distance with the jacket suspended from both Thialf cranes ranged from 200–300 nautical miles (1 1/2–2 1/2 days sailing). The final cuts and the jacket lifting required relatively low sea states. The wave climate for transport was determined with the assumption of a preceding weather sensitive operation, which is different to a transport that assumes a start at a random time. Model tests for these design sea states have been performed to accurately assess the Thialf dynamic behavior at its shallow transit draught. Additional analyses were performed to confirm the vessel-jacket dynamic interaction. During transport the so called ‘restraints’ gripped around the jacket corner legs, restraining the structure horizontally and preventing side loads on the cranes. During the three transports, motions have been measured and dynamic behavior corresponded well with the analyses. Removing and transporting these jackets as a single piece was a unique operation. The method worked well and resulted in a predictable, safe and time efficient jacket removal. This paper will address the removal method, including structural aspects, model tests and full scale verification.

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