Christmas tree at the wellhead technical indicators, we often encounter the following parameters: pressure, dimensions, material grade, temperature rating, PSL (product specification level), PR (performance requirements).
1. pressure rating and size generally determines the user directly from the site conditions.
2. Material grade API divide it into seven levels, see Table I;
Minimum requirements for the material grade material
Body, cover, end and outlet connections pressure control member, the stem and the mandrel type hanger
AA- general use carbon or low alloy steel or low alloy steel
BB- general use of carbon steel or low alloy steel
CC- general use stainless steel
DD- acidic environment ¬ carbon or low alloy steel or low alloy steel
EE- acidic environment ¬ carbon or low-alloy steel
FF- acidic environment ¬ stainless steel
HH- acidic environment ¬ corrosion resistant alloy corrosion-resistant alloys
AA, BB, DD, EE using carbon or low carbon steel (commonly used in 4130)
CC, FF stainless steel (commonly used 410)
HH the body use 4130 or 410, the contact portion with the fluid with anti-corrosion steel (commonly used 718 or 625)
3. Temperature Level API, there are strict requirements, see Table II:
Temperature grading operations range (℃)
K -60 ~ 82
L -46 ~ 82
P -29 ~ 82
R at room temperature
S -18 ~ 66
T -18 ~ 82
U -18 ~ 121
V 2 ~ 121
4. PSL - Production Specification Level Product specification level
API provides four kinds of products of different technical requirements specification level, respectively, PSL1, PSL2, PSL3, PSL3G. API 6A 19th new PSL4, the index is actually the raw materials, spare parts processing various detection and recording before and after the test content larger the number, the greater the range of the recording, the price is higher, API 6A to what the environment By using what level, there are clearly defined, see Schedule III
